From the M25 on to the M23, take Junction 10, then A2011, which will bring you up to a roundabout with a flyover on it (on the left is the Ramada Plaza Hotel). From that roundabout take the 4th exit, passing Go karting on your left and go straight across (2nd exit) at the 2nd roundabout.
At the next roundabout go straight across and Thales will be on your left. This will bring you up to another roundabout, go straight across that one and about 1/2 mile down (passing Topps Tiles on your left) turn right into Cobham Way. We are at the end of the road on the right.