In reply to gfpowell:
Portland(sport)/swanage (trad) are your best bet, but they aren't a short drive.... 3hrs or so to portland, a bit less to swanage on a day with good traffic (although it may be a lot better now following the olympics relief road - haven't been down since last spring)
Otherwise there's southern Sandstone around an hour away, no leading, but despite its reputation there are some interesting routes worth a bash, but make sure it hasn't rained for a while before you head down, and read up on avoiding contributing too much to additional errosion.
A weekend in font is more than possible as another alternative.... either the dover route (4-5hr drive in france) or newhaven-dieppe night ferry which drops you in France about 6:30 AM, and you can be climbing by 9 on a good run