the cotswolds or late minute visit

Bath is pricier than some locations, but still cheaper than London. Two days there would be perfect and you can avoid needing a car by taking a tour with driver (Mad Max is excellent) from Bath if you want to see some of the Cotswold villages.

Canterbury is a shortish train ride from London and is a fun little town. The cathedral is very nice. Brighton is on the coast and is also a short train ride away (even closer if you fly into Gatwick airport). There are fun things to see and do there in addition to the beach.

Neverne, I'd also suggest Bath! It's a fantastic and historic location, and as someone else mentioned you could take a Mad Max tour to Stonehenge, Lacock (a National Trust village) or the Cotswolds. There's also lots to explore around Bath. Be sure to take one of the excellent local walking tours! Bath is easily reached from London via rail or National Express Coach. If you're arriving at Heathrow, the NE Coach stops there anyway, so no need to even go into London. You'll arrive at Bath Spa station, and can use a Taxi from there to your Hotel. Happy travels!

Cotswolds is a wonderfully charming area- but almost impossible to see without a car. Although i am not excited about Bath, there is interesting stuff to see and it is a good starting point for a tour to Cotswolds. Other areas to see on your own- Salisbury, neat little town, wonderful cathedral, and there is a bus service to Sonehenge. (so its good to have two days). We love the Kings Arms pub/inn/hotel in town. Not upscale (bathrooms down the hall). walking distance to teh cathedral and the station. Or do something different like brighton or even one of the thames side villages west of London- (Henley, Richmond).