Not according to the company’s website…
…but I think there may have been a transition model floating around between II and III.
Thanks for the link! That explains where the MK I, MK II and MK III terminology comes from … it is used right there on the companies website! Who would have guessed to look there?
So, given that they omit to mention the intermediate model with the bump, that Mr Gumby showed, and that it occurred before MK III came out and after MK II, I guess it makes sense that people refer to that as MK II.5 or MK 2.5.
I guess we could add some alphabetic letters to mix of Roman numerals and numeric decimal places if we really wanted to complicate things further. 
I should add that I bought a couple Mark I (circa 1980) from a member last year (I think). The windway was juuuust slightly higher than mine,2 of which I purchased in 1980. So I guess that would make a MarkI I/2 designation. Or something.
My father was a crack machinist,but all I have are his micrometers. So don’t ask me to take measurements. Sorry.
I think they play just slightly louder than mine.Very slightly. Original owner blu-tacked them,so that may make the difference.
I’ve noticed this apparent difference too, but don’t have a way of measuring it.
My own Mk 1 was bought in the first week of July 1980 – I can date it because a relative had just died and I got it to play a couple of tunes in his memory. I don’t know the history of the other Mk 1, which I bought from an eBay seller.
The windway height on mine appears to be fractionally lower than the eBay whistle. However, it’s possible my eyes are being misled by the difference in colour. The 1980 one was very sharp, and dunking the head in hot water to melt the glue made the colour of the plastic lighter. The tuning on the eBay one is pretty much spot on, so I haven’t needed to move the head.
I also think the eBay whistle is fractionally louder. They both have the lovely rounded tone of old Feadógs, but the eBay one seems a bit more robust.
All a bit subjective though. 
They’re both lovely whistles.
Wow I come back and the thread has gone down the Feadog rabbit-hole!
I will say that as far as I know there are two kinds of “Mark One” Feadog.
My first one, which is the best one, is darker green plastic (left). There’s a reason it has all the teeth-marks!
Later I bought another one with the lighter green plastic (centre).
When the first kind came out, and when they changed colour, I have no idea.
The right-hand one doesn’t play up to the standards set by the earlier ones.
I’ll call them MkI ausf.A, MkI ausf.B, and MkII.
Oh dear. I thought I had an ‘original’ but mine looks like the B version. I still love it though.
Have either or both of yours, if they catch the light right, got radiating ripples a bit like a fingerprint on the sides?
I think my MK1 is the B version too. Aside from the color difference it seems that the very end of the beak is more chamfered at the edges on the A version than the B version, and the angle on the high point sharper. It looks like a slightly different mold not just a different material.
And by the way, pancelticpiper, I think the poor playing one on the right is a MK3 (current version) not a MKII, for what thats worth.
Yeah, I also think the third one’s a Mk III. The head of the Mk II is similar to the Mk I, but without the vertical chamfers. It’s also narrower.
My Mk II plays better than the Mk IIIs, but it’s not as pleasing on the ear as the Mk I.
Yes I see what you mean, the right-hand one in my photo comes all the way down straight on either side of the windway.
I see that the MkII still has a bit of outward flare towards the bottom.
Here they are from an angle
and just the two MKI’s
Does the right-hand Mk1 have the bottom of the windway exit sloped back into the hollow, with the LH one having it on the plane of the windway top?
I don’t know about Pancelticpiper’s, but neither my Mark Ia or Mark Ib has a slope here. They both appear to be cut dead parallel to the windway top.
I think there are a couple of small differences, though. To me, one of the mouthpieces feels chunkier than the other – the curve on the back of the beak seems different somehow. From the photo it appears that I’m imagining it (and I may be), but as soon as I got the second one I was conscious of it.
Also, the end of the windway appears to be a tiny bit different. I don’t know if you can see it, but the whistle on the right has two small notches cut into the top surface, whereas the left-hand one doesn’t. Between these notches the bottom edge of the windway is slightly cut down.
The difference between them is barely 1mm, it and could just be a moulding anomaly – perhaps it’s supposed to be there on all of them, but failed on the left hand one. I’ve only got these two examples to go on.
https://www.dropbox.com/scl/fi/txpkt48likhy7etodpi89/Whistle-notches.jpg?rlkey=hyb4pugjkvpjbfeb8i2pe22l2&st=8v3v3rk3&dl=0
PS: You lot have turned me into a whistle nerd! I may sue.
I may not have been clear. On the window end of the windway of Pancelticpiper’s left had one the area below the windway (with the debris) catches the light much like to area above. On the right-hand one, which seems to have a filling of some sort in the the cavity, its like that in the left (on the photo) but in the middle looks thinner. Looking at it up the socket on mine both sides are extension of the plane of the other side but that stops at arcs that match the cylinder of the socket. looking at the blade throug the windway something similar happens and the bottom of the blade has the curve of the socket.
It looks like the inside of the mould was a rod that was cylindrical as far as the windway and then had a notch in in the top where it was shaped to form the cavity.
I must work out how post a photo.
An uncle who left us decades ago was a toolmaker who machined moulds for various things. He could probably have told us a lot about whistle head production. When I was small he had a job making the moulds for some tooth rotting boiled sweets I was eating. He said the volume was critical for all the different shapes (fish, frogs etc) so that they were the same and there was a whole number of sweets at the weights they were sold in. Having to add an extra sweet to get over the weight could take all the profit.
Ahh, I think I might see what you mean.
it’s hard to photograph the inside clearly, but in both my examples the depth and shape of the strip of plastic separating the windway floor and the void looks about the same. It’s flat for the width of the windway, but you can just see that it starts to curve at the edges – so it sounds the same as yours. (I can’t work out how to post photos either, hence the links.)
I’d never thought about sweets having to be moulded, but of course they do! They probably nearly as many challenges when making the moulds as whistle makers do.
@pancelticpiper I apologize for the time it’s taken me to follow up on your request. If I’ve understood you correctly, and I believe I have, the measurements are as follows:
Bore diameter: 12.43 mm
Length from blade edge: 264 mm
I’m trying so hard to love this whistle but am struggling.
I think my Feadog may be a first gen. Correct? I did buy it in the early to mid 80s.
Sorry been away from the laptop a while.
I have the two Mk1 heads here and there are curious differences despite the similarities.
Most significantly the MK1B appears to have a higher windway.
I can only get the very tip of my calipers in the beak end, so take with with a grain of salt, but I get
MK1A .52"
MK1B .58"
I can’t get the calipers in the window end. Just eyeballing they look the same.
The bottom edge of the base of the windway (where the head’s cavity begins) viewed from the socket is clean straight across on the MK1A but a sloppy irregular cast on the MK1B.
Also the MK1A socket has a slightly larger bore.
On either of the Feadog brass bodies (which seem the same) the MK1A is a loose fit (needing something to keep it in place) and the MK1B is a proper fit.
With calipers I get
MK1A .49"
MK1B .489"
It’s a tiny difference on the calipers but a significant difference on how they fit the body. It’s also clearly visible when you view the sockets side-by-side from the open end, you can see how much thinner the MK1A is around the socket.
Another thing is that the A has a slightly longer socket, the overall lengths being
MK1A 2.26"
MK1B 2.241"
On neither head do the moulds at the beak end match up well.
The MK1A has a subtle seam going all round the back where the points of the “ears” are, while the MK1B shows a small but clear mis-align between the moulds there.
About colour, in person it’s not only that the MK1A is slightly darker, also the green is a more saturated Kelly Green, while by comparison the MK1B has a more muted green with a very slight olive tinge.
There’s a tuning difference, the MK1A having more true octaves while the MK1B has the slightly flat 2nd octave often encountered with Generation whistles.
A very subtle difference, which suggests two different “sculpts”, is that when viewed from the socket end you can see how the round back morphs into the “ears” differently on the two sides, the two heads being different, sort of mirror images of each other. (If any of you are nerdy enough to have looked at the 1977 hand-sculpted Star Wars “stormtrooper” and Darth Vader masks you’ll be used to spotting asymmetry.)