I'm off for a week away with the wife next week, Mostly kite flying and surfing (if there is any). Is it worth taking a bike? I'm not going to be able to go as far as Kielder, But is there any decent riding near the coast? Staying around Blyth I think, but fairly mobile. Any suggestions?

You could do some of this route (Sustrans):

http://www.coast-and-castles.co.uk/

Follow the route of the Great North Bike Ride, Blyth up to Seahouses. If you want a shorter route just do the section from Druridge to Seahouses

Surfing, there is plenty, 10 miles down from Blyth in Tynemouth, one of the uk pro tour sites

Rothbury's not too far inland and there's loads of good stuff round there. Also Wooller Common.