In reply to simonacarr:
1) I think after such a shit winter Malham is wetter than it usually is this time of year, but Raindogs is one of the drier routes (a pocket low down often seeps but it is common to put a plastic bag/foil in it). I was trying it in Feb-March a couple of years ago. There's a useful facebook group for conditions updates.
By April time I'd be more concerned about it being too warm on a sunny day. I seem to recall it gets the shade from about 3pm
2) It can be busy, but you should be fine midweek. I never found it so busy that you couldn't try it, but it depends how anal you are about sharing a route with others, having you own draws in it, other people greasing up your holds etc...