G'day Dullbird :)
If your series is a S3 or late 2a,it should have the threaded hole in the rear of the gear lever mounting bracket, with which you can fit the brass series 3 stop lamp switch,this is the original type of fitting, as the lever comes back and depresses the switchthreaded nut adjustable,or, you could get a gear selector complete from a wrecked Ser 3 4cyl and just mount it in place of the 2/2a one the power leads are 1 from a ignition source,(solenoid) and the other goes to the lights, best by following the brake line along, I have a reversing light and a rear fog collision which are the rectangular Defender ones, all switched manually from the dash by lit switches.:)
cheers

