Ok M8 you need to contact these people,They were warning people that the p38 remotes bought off places like ebay would not work on any other car without the ECU that the key was coded to.They have been working on the p38 fobs for at least 2 years that I know about,They appear to be a reputable company.
If any one can help you then it will be these guys,and it won't be at dealers prices.Try phoning them and explain your predicement.Bet they soon have you on your way
REMOTE KEY LTD
MG - ROVER - LAND ROVER ALARM & IMMOBILISER SPECIALISTS
0121 580 9090 mobile 07930 178 422
mail@remotekey.co.uk
7 Kesterton Road Sutton Coldfield West Midlands B74 4JP