I thoroughly recommend Dartmouth in Devon, its gorgeous, and nice, accessible from Berkshire.
2) Lots of lovely cottages, apartments and hotels available
3) Has a great choice of restaurants, boutique shops, art galleries and watersports.
4) Usually glorious weather at end of June
5) Next to the sea and river so lots of opportunities, can be active and kayak and white water raft, or relax on a luxury yacht or ferry, up to you!
We have been going for the past ten years and always go back, its the perfect choice, www.discoverdartmouth.com