Rhiannon,felt awful that I'd forgotten to put any more, but then saw that you had logged on from Barbados (you addict you) so hopefully this will get to you and be some help.
Barbados is the only country in the world that Mcdonalds has tried and failed to conquer. This is mainly due to the wonderful "Chefette". they do good, cheap fast food (the roti's are wonderful) and some of the bigger ones have bbq barns, with big play areas for the kids. There is a very good sports bar in Rockley called Bubbas for something a bit more sit down. St Lawrence Gap has some very nice restaurants (Pisces is wonderful) at slightly more reasonable prices than the west coast. If you feel really lazy, the KFC at Rockley will deliver!
Tuesday night buffet at the Waterfront on the Careenage in Bridgetown is v. reasonable (BBD50 all in) you might need to book. The pepperpot is great (a sort of oxtail stew) but the kids might not like it. They will like the live steel pan band
The BEST thing I have ever done in Barbados was to swim with the turtles at the Lone Star beach. No private beaches in Barbados so you can just go theri, and their is usually a guy selling bags of raw fish taht you can feed to the turtles (but watch your fingers. DD probably won't be able to see them (they tend to stay at least a couple of feet under the wter) but ds should love it. If you want to do it properly, you and dp can "snuba" - like scuba but tank stays in a float and there is no need for training - leaflets for it are in all the tourist spots.
Harrisons cave is fun - lots of stalactites and stalacmites, but the film beforehand is a bit boring.
My favourite beach is down at the old Hilton (now knocked down) at Needle point. Nothing to do, but the waves are great and the beach is usually deserted apart from a few locals boogie boarding. definately try to take a trip to along the East coast road, specially to Bathsheba - its a totally different Barbados, but you should also try the west coast - all the beaches are open to the public so you could even go and park yourself on Sandy Lane beach and do some star spotting. Mullins is also good.
You should be fine with Mossies this time of year, hopefully you haven't already discovered the awful sandflies.
On Xmas day, the church services are something else - my dh still remembers being taken to a service by the housekeeper that started a 6am, and not getting out of the church until midday!
I am now getting v. v. jealous. Hope you get this, and that you are having a great time.