Just my 0.02p worth, but after years of looking for 'the' high D whistle I bought one made by Stephen Harper and have never looked back. Loud without being strident, nice in the mouth and under the fingers, and less susceptible to tuning problems than some of the high-end whistles, and most importantly of all of course, a lovely rich full-bodied tone across the whole compass.

So, IMNSHO, if you're looking for a decent D whistle I'd thoroughly recommend you try one of those.