I just came across this thread and thought I would add a few words.
raindog1970: As for the differences between Bernard’s and Colin’s whistles, there really are very few… which is really what you’d expect since Colin was taught by Bernard.
Here’s what I have noticed by comparing my four Overtons:
(1) Colin signs and dates his whistles, and Bernard doesn’t.
(2) Colin smooths the edges of the finger holes, and Bernard doesn’t.
(3) Colin sandblasts the inside of the tube, and Bernard doesn’t.
Thanks Gary, that is the main differences. The hole sizes and placement of the finger holes on all of Bernard’s whistles and mine will be different, some by very little some by a lot as we develop this independently.
nickt: I’m not sure that’s still the case, my BO low D has Bernard’s “new” close hole design (for 2-3 years now) and plays gloriously. Mind you, Colin and Bernard do keep in touch regularly so Colin ought to know…
As far as I know Bernard’s standard Low D is a wider stretch and a shorter stretch on request whereas my standard Low D is the shorter stretch and big hole/wider stretch on request. You and Bloomie are right, we do keep in contact by phone a lot and I was over there not so long ago.
Bloomfield: Loren recently pointed out that tha backpressure/low breath thing, the hallmark of Overtons, is not quite true anymore because Colin will make you easy-blowing whistles that have different breath characteristics but still have that wonderful Overton sound.
This is quite true. I have enough experience now making these whistles by hand to know what effects what in tone and playability and if anyone does have anything specific they are looking for I would recommend coming direct as the whistles that I supply to shops are fine whistles but there maybe a spectrum of playability and tone amongst them. I know from myself and players I met over the years, they all may have different ideas of what is their favourite whistle, what suits one player may not suit another. Loren has been telling me for the last couple of years to stamp hard or soft blow on the whistles so people may have an idea but what I call hard and soft can be different from other players. Besides which what about the ones that are somewhere in the middle…
JoC: Does that mean mine’s a Bernard? It’s not signed and has a larger reach than the (very few) other overton low Ds I’ve tried. I bought it from Hobgoblin 5-6 years ago (I tried all the low whistles they had and that one was best).
Bernard had stopped supplying Hobgoblin for a few years and he started supplying them again in 1998. All whistles made by Phil and myself would have been stamped Overton (as this was part of the license agreement) or a few were stamped OV. I also either stamped CSG before the Overton or I signed it inside as I still do. I started signing them shortly after first making them so they could be identified later if need be. If it has no Overton stamp on there then it is not an Overton no matter what the seller told you. Bernard first started stamping his whistles 20/25 or even more years ago after a shop in Ireland started putting their sticker on the whistles saying it was their brand. I saw one of these last year in Rudolstadt.
Brendan: I too would buy any of Colins whistles blindly. I have a low D, low F ,two low C’s and a low Bflat. They are all brilliant, there is no variation in quality. I think it’s fair to say that Colin can make you any whistle you want, as long as you know what that is! I recently tried lots of his whistles including several low Ds. They all had slightly different qualities but I would have gone into a recording studio quite happily with any of them. Great customer service too!
Bloomfield: (Although I would buy any of Colin’s whistles blindly.)
Danke fuer die Blumen (thanks for the flowers) and the trust in my work, it is much appreciated. 
Myself and Brigitte had the luck to meet up with Brendan and his lovely wife recently. It was great to hear a few of his tunes from the CD played live. He was kind enough to play some of them slowed down so I could have a chance to learn them. I am working on Kushkas/MaverickAngels at the moment. Well so far I can play it quite o.k. at the speed HE calls “slow” but at “normal CD” speed I drop out after the first bar
Same thoughts as Bloomie, incredible CD, the more I listen to it the more I appreciate it. If you have not got it, go for it as it maybe hard to find a copy in the near future.
Hope I have not be too long winded here.
Tschüss
Colin