Doncaster, Andy?? Not far from me, then. I like the thumbies, mainly because my thumbs are no longer strong enough to change down (i.e. onto bigger cogs ) comfortably with the pushing motion usually required. I found I ended up using the 'heel' of my hand, and the thumbies suit much better.
My wife rows at Hexthorpe most Saturday mornings, we must meet up there sometime . . . . .
Lewis - Sheffield