There several buses which go through Rottingdean along the a259 to The White Horse Hotel bus stop (or opposite). Then its approx a 4min walk to The Grange.
You can also get the no.2 bus at stops by Tesco, the High Street, The Green and by St Margaret’s Church.
Brighton and Hove Buses:
Buses no: 12, 12a, 12x, 14, 14b, 14c, 27, 27a, 27b.
View more information about their service here.
The Big Lemon Buses:
Buses no: 47
View more information about their service here