areas to buy a house within commuting distance to london?

I am looking to buy a a flat/house in a decent area somewhere between bristol and london, preferably village like, with river/ boating areas or with the coast near by. I would like good transport links to london to continue working here.
Can anyone recommend an area that would suit a late 20's /early 30's couple?

Any recommendations & rough price of travel would be greatly appreciated.

many thanks!

D

---