In reply to jonnie3430:
Just to complete the argument - I'd go for a 16cm as the standard 'decent screw' length. In the UK you'll be lucky to find ice thick enough for a 22 and even if you do, there will probably be a better alternative belay. If not, your 19 will have to do. Don't think I've ever carried a 22 in Scotland anyway - fat water ice thingy really IMHO.
A bulldog/hook is useful. You might want to consider a 'get out of gaol' kit of a bulldog, a blade peg and another peg that is a bit thicker than both of those. You'll use the bulldog and be very grateful for the others when you need them.
Screamers - first screw north of the belay gets a screamer. It might do nothing, but on the other hand it might, and anything that prevents a leader fall onto a rubbish belay is a winner. I have not tested one, and have absolutely no desire to do so. It's part of my little psychological shell. I have a second screamer - that goes onto poor gear that might stand a chance, or on more decent gear that looks like it might become very lonely.