Brett - without doubt, the Rose blackwood. Similar characteristics but stronger tone and very clear pure notes.
I actually got my Dixon tunable as a travelling whistle so that I don’t have to take my Rose to risky places, knowing that the sound is similar. Trouble is, I’m playing the Dixon less now because the Rose is that much better (good as the Dixon is).
As far as I’m aware, Tony only makes polymer whistles.
I paid him a visit last year and he explained that he prefers polymer, as it’s easier to work with and allows him to make a quality instrument at an affordable price.
He does use hardwood for his flutes and pipes but is concerned about the source of such materials. His suppliers assure him they come from sustainable forests but do they really know and would they tell you if it didn’t? He’s a great guy check http://www.tonydixonmusic.co.uk/ for his product range.
Cheers
Joe