Thanks for that Allan, I actually started out with something similar which evolved into these, and was happily extolling the virtues of the fly I'd 'invented' to Mr. Nelson until he (not unkindly) burst my bubble pointing out they were effectively Dirty Dusters and had been around for ages.
I know there's very little new in fly tying, mostly just variations on a theme. I'm not a great follower of patterns, preferring to sit down and make things up for myself and funnily enough I'd arrived at the tying as an alternative to the DHE which while I
can tie, takes me longer because I find deer hair a faff. It also doesn't seem to float as well as these,
for me anyway. Having subsequently read Bob Wyatt's description, it seems one reason he came up with this duster variant, which could be fished as a simple alternative to his DHE, was for lazy beggars like me. For now they've nigh on replaced DHE's and Klinks in my box, although I will need to sit at the vice at some point and be slightly less lazy I guess.
Andrew