When living with my family in Hampshire we often visited this idyllic little village of New Alresford. The village has several nice pubs with The Globe on the Lake as a favourite for a light lunch. Take the train from London, Waterloo Station to Alton (1 1/2 h.) and board on the cosy steam train, The Watercress Line, to Alresford.
This old steam train is by the way “dressed up” like Thomas the Tank during special weekends. The village has several tiny antique shops and some really nice clothes shops. Of course you should not miss the walk along the river. Start out from the old fire station at the bottom of the square. The area is known to grow the best watercress around and the pubs normally serve a tasteful watercress-soup. A really good day out when visiting London!