Red bison heated screen kit

Hi all, I know a few people on here have one of these after reading some other threads. I've got one was brought as a present for me for my rebuild 200tdi 110 have had the screen fitted for a while and I have just come to fit the loom and control box and have realised its got the genuine land rover switch fitted. So I would like to swap it for a carling switch as I can't fit the genuine one, have been on the red bison site and as others have found its useless . So I wondered if one of the people who have one fitted could tell me which wires are connected to where on there carling switch please ? The wires I have are red , purple, black and orange.
cheers Ian

Can any one help have tried to cut a hole for the genuine switch but it won't work or will have to buy another loom as am not sure if the wiring in the carling switch version is the same as mine.
Cheers Ian