Thanks for the advice chaps.
Went this morning and caught 2 on sunk daddies - superb. Had to leave after a couple of hrs to take the wife shopping, much to my disgust.
They wouldn't look at the drys though, I started on them but gave up. Also, I degresed the leader and found that that the fly and fly line gradually came closer together as the leader sank. Probably doesn't matter but I just don't feel confident with so much line hanging underwater (a hang up from my floating crust/chub fishing).
Since taking up fly fishing the whole leader question is the one area that I have the most doubts over - too long, too short, tapered, non-tapered etc. Its something that will come with more experience i suppose.
I'm definitely loving fly fishing though - wish I'd tried it sooner. Can't wait till I'm a bit more proficient, then I'm going to go Chub hunting on the fly next summer - Heaven!