if it is your switch then u dont need to re-pin the key it connects on to the ign lock.
http://www.roverparts.com/Parts/STC1746.cfm
if u need the ign lock then u can have someone re-pin it. i had mine repinned so i would not have 3 keys. the PO had issues w/ the PS lock and i have a key only for that door. sometime i need to fix my PS lock (only unlocks) and will re-pin that so i have 1 key.
edit: u might find the part that u need from someone that is parting out a 95 rrc or a early disco (94-99). i have one from my dads 91 rrc but will not work on the 95 rrc.