Thanks all!
I hadn't thought of the sea life centre, like the idea of going somewhere he will enjoy :) we are going to Scarborough so can do lots of pottering about and also have friends to visit but I wasn't sure if there was stuff I'm missing that Sam would like though I know he's still very young!
We have never actually had a UK holiday together so not sure what we would do usually! I suppose it's the nights that will be most different with a baby as he's such a light sleeper I shouldn't think we'll be out in the evening much!