If you want to be right next to the sea, I do lurve the Saltdean & Rottingdean area, which is only 5 miles from the city centre.
It has very good local schools, solid family houses at reasonable prices, and Rottingdean has some excellent village pubs.
It's far enough away from the *cosmopolitan* delights of central Brighton for loads of peace and quiet - incidentally it has one of the lowest crime rates in all of B & H - but the city centre with all its facilities is only 10 minutes drive away if you need it.
It may only be 5 miles but it would take 40 mins to get to Btn station to commute to London. The coast road is terrible when the schools are back.