Note that the postcode on Google Maps takes you to a road behind Papplewick, from which the school is inaccessible. The map above takes you to Papplewick - it is on the right-hand side of the road.
Go south on the A355, following signs for Windsor (A332)
At the big roundabout just past the Windsor floyover take the 3rd exit, signposted Winkfield/Bracknell (B3022)
Right at the end, then across the mini roundabout and past Legoland.
First exit at the next roundabout, then follow the next roundabout until you take the 3rd exit (A332 Ascot)