Andy, just to clear things up a bit, Colin Goldie makes what he calls a “Standard” tenor D. This has smaller holes that are placed closer togather. From what I have read it is one of the easiest reaches out there. Colin also makes the Big Hole tenor which is made to the specs of the original Bernard Overton low D. This is the one I have and it is amazing. I believe you can still order a whistle made from Bernard, but I do not know if he makes the closer reach that Colin has designed.
Don’t quote me on this, but I think if you order an Overton from Hobgoblin it will be made by Bernard. If you order from another source chances are it was made by Colin and will be his standard number.
If you are serious about getting an Overton, you can always contact Colin via email.
Andy, just a word of caution about the Overton. I can’t comment on Colin Goldie’s Overtons because I haven’t played them but I’ve been playing two of Bernard’s low Ds for a while. If you’re having problems with high A and B on the Howard then you’ll certainly have similar problems on a Bernard Overton Overton if they’re as hard blowing as the two I have. I own a new mouthpiece Howard and find the top notes fine, but that’s probably because I’ve had a lot of practice on the Overton. Still, I agree with the others that the Overton is worth going for. It is a beautiful instrument. In Scotland it appears to be easier to buy a Bernard Overton Overton at retailers. My local music shop has a low D in stock at the moment. I haven’t seen any of Colin’s instruments retailing locally. All the best with your low D whistling.
I have an Overton Low-D, made by Colin in '99. I can get the high A and high B clearly. Coinnleach Glas an Fhomhair (On the Stubble Fields of Autumn) has become one of my favorite airs to play on it along with An Feochan(Gentle Breeze). Both tunes have high clear B’s with the later tune having a C# to high B jump that is easy to play on my Overton.
I don’t have one of the large hole models. The finger holes are plenty large enough for expressive playing of slides and other ornamentation. I do not have large hands and found the Overton to be the most comfortable to play compared to other whistles I tried.
Hope this helps you …