Thanks for that - We're looking to tour only for a week or so, so the size of the place shouldn't really be that much of a problem.
Indy, funnily enough. one of my other options is Andalucia, esp the area around Grazalema. I went there a few years back (non-cycling) and really liked the area. There was a wonderful road from Arcos de Frontera to Gaucin, which lasted about an hour and half driving and on which we saw about two cars. It rose gently but steadily along a river valley and looked like something out of the Americas. I'd long to go back, but not sure about the practicalities of getting there from the UK with bikes.
Our other option is the German Baltic, which while totally opposite to Spain, is a place I'd love to see.