Hello everyone, I was searching for the second high D whistle (I was learning to play on Clarke Original), wishing to find not very expensive high-end. And found out that Merlin makes 7-holed high D`s, so you have an opportunity to get natural C of the 1st octave. As I know, Goldie also makes such upon special request. Are these whistles really good, did anyone try them (merlin or goldie, no matter)? I have just fell in love with that merlin D7 and I consider it to be very useful for me. But, anyway, it is very interesting to know, what do you guys think about it!
Lots of people use whistles and flutes with a thumb hole for the C-natural. Just to try it out, I drilled my own in an old Walton’s whistle, and it works great. I decided not to get used to it, though ---- cross-fingering works fine, and I don’t feel like retooling my brain or drilling out all of my other instruments.
Very true! But let’s remember that there are two seven hole whistle formats which give you a C natural on the D whistle. What Crookedtune described is a thumb hole located on the back of the whistle which the thumb of the top hand operates.
There are also a number of D+ whistles where the seventh hole is covered by the little finger of the bottom hand. I think this may be what the original poster is referring to. Such whistles are made by a number of makers too. Goldie makes one called a soprano D with bottom C. I think Paul Busman makes one as well. I have also played a Silkstone D+ which was very nice. I have made my own whistle with the bottom C. Proper placement and sizing of the bottom hole can be troublesome for some little fingers. They are “little” after all (and my pinkie is not entirely straight either)! But such a whistle can work quite well for many hands. They make playing tunes with a low C possible.
Goldie makes good whistles - period!
Merlin whistles have had mixed reviews here. You can use the search function to read what others have experienced. I have not seen a review of the Merlin with a bottom C hole.
Hope that helps.
Feadoggie
Quite right. The OP was referring to a low C note. Sorry to confuse. 
Oh, thank you, thats exactly what I was speaking about! Sounds really interesting, I think I wouldnt have troubles with reaching the 7th hole with little finger - so its definitely worth a try. Unfortunately there are not so much info about Merlins, even standart high Ds… But their low D whistles are rather good for their price, according to several posts here. So I wish high ones are qualitative too
I have a Merlin Excalibur D7. It is very well made and I believe in experienced hands it can perform well, however, this is definitely not a whistle for the beginner. Due to the design characteristics of the mouthpiece it requires a fair amount of push and you can “lean” into it as some would say. Because of the push required to produce viable sound it is a very loud whistle.
I am about to have an after-market “practice” mouthpiece made for it so I am not thrown out on the street for disturbing the peace. 
I make a 7-hole whistle in both metal and wood. Being custom made to the player, I can adjust the 7th hole position to suit