I love North Cornwall and am off to Mawgan Porth in August. Went to eden project when it first opened and am going to go again this year to see how much it has changed. Stayed in St Ives last year and ate at the restaurant on Porthminster Beach. The food was really fresh and not too expensive. If you want to go body boarding/surfing, then Mawgan Porth is good - just round the coast from Watergate bay, but not so trendy so alot less people there. There is a surf shop to hire wet suits and boards and a cafe and pub. I'm sure you will have a great time - we always do.