I will add, if you have access to a car, a great overnight trip (stay near by the night before) from London is to do the early morning, pre-opening Stonehenge v

I will add, if you have access to a car, a great overnight trip (stay near by the night before) from London is to do the early morning, pre-opening Stonehenge visit (book it a bit in advance and you can get right up to the stones with hardly anyone around) and then head over to Bath for lunch and the afternoon.