I agree with Blink about flexibility on destination. I have a couple destinations "pre-planned" on my want to go there at some point list, and a lot of times I make my pick in the morning.
Anyway, to add to the suggestions that could enrich your weekend flight, why not make a short stop before you get to Dunkeswell? Compton Abbas Is a lovely airfield and conveniently positioned between Elstree and Dunkeswell.