In reply to GoodClimbing:
The Dorset coast has plenty of limestone routes, some of it is quite polished but gets better quality the higher in the grade. Be expected to be spat off a couple of 6b's at Dancing Ledge! Plenty above 7a, mostly overhanging which start off with technical moves on tiny holds.
The routes in the Dorset Rockfax book run from Swanage to Portland, with Portland being a Southern Sport Climbing Meccah. Swanage has more of a mix of Trad and Sport (bouldering to be had too).
Swanage can be a sun-trap at all times of year (south facing) if the weather is good but does suffer some seepage if it's been wet. In the summer I've never had any issues other than it can get a bit busy at the weekends.
Plenty of places to park up and camp, but the campsites are fairly cheap, quiet and well equipped. Tom's field in Swanage is basic (showers, electric hookup) but well located to most of the Swanage crags. I've only been to Portland a few times, so can't really comment much on the area. It will be difficult to park up for a duration and not be expected to be moved on or pay for parking as most of the area is privately owned or have car parks that you have to pay for.
Depending on how long you stay, the routes would occupy you for a full season I reckon - more than enough to do in a few weeks.