DAMN.. £90.. and a charge for coding it.. thats a rip off
is it possible to just buy another black with with a circuit board (like a second hand one off ebay or something) and just get that re-coded??
Have you attempted to call an auto electrics place yet? Some are even mobile so they will come to you at a time which is convenient. You will however have to actually find a number, then pick a phone up and ring them yourself.
Sometimes forums have the answer, and sometimes it just takes a little bit of nouse and common sense.