It's a C&CC site at Keswick. The National Trust site is at Low Wray on the Western shores of Windermere. Both have direct lake access. Both have reviews in the UKCS listings.
Park Foot on Ullswater, camping field right on lake, we used to go a few years ago with our inflatable boat, great fun :) enjoy, exactly as you say just pop on and off the water as you please.
------------- Donna
Don't forget to leave a review of the campsites you have visited this year or last!
Coniston have a couple that are next to the lake, although many many years ago you used to be able to camp right next to the lake, now they have moved them back so that snotty people in big houses down the lake cannot see the tents!!!