In reply to Will Collett:
As the moment, from the forecasts I can see, I'd go to Swanage - looks good all week.
My brief assessment:
Early in the week - SW looks ok (options like Cornwall, N Devon), as does N. Wales (Mon/Tues) as well as Pembroke.
Mid-week onwards - Swanage and Portland look like the driest. You've got trad, sport and bouldering options there.