Thanks for the suggestions - jellystone a tad too far!!
We ended up at Scorton picnic site - recommended by someone.
Just for future reference if anyone suggests you go there for a picnic, do go but don't do what we did and sit around the car park on a picnic bench thinking that was it!!
went for a walk after our lunch through the woods and then realised why everyone had been staring at us sat on the bench by the car park - when you walk through the woods there is plentiful lovely areas to sit by the riverside having a much more scenic pinic!!