In reply to ShortLock:
quality easy grade sport climbing is a bit thin on the ground, though robin proctors scar near clapham has probably has the best 6a's around (plus most tops are snap links so don't need to thread the belays, which might be a plus when you're starting out), and there are a few easier 5's at high stoney bank. if you're at richmond a good way to start would be some of the great bouldering around the area. you're close to scugdale, which is in the rockfax northern guide and the new north york moors guide. bring big bouldering mats.
plus find someone experienced to take you out leading to teach you all the "tricks". or get on one of the courses people run in the area like:
http://www.grittrackandtrail.co.uk/mountaineering-and-hillwalking-courses/l...