2002 Impreza WRX (Bugeyes)
Had to have a new windscreen fitted at home.
Checked the car over and found the driver side motion sensor mounted on the screen pillar was smashed...the fitter was long gone.

Made a temporary repair to the shell with epoxy putty but need to replace.
Works but looks horrible.

Have located a used one for £12 but don't want to tackle the job without a clear idea of how to do it. No local dealer now Walldonway has gone so would greatly appreciate any help...it looks fairly simple but I don't want to bugger up the alarm through ignorance!

Thanks in advance