http://www.wps.com/LPG/
start here, he at least is in the CONUS (lower 48 to the rest of us).
For the UK, Google has it:
http://www.google.com/search?q=lpg+c...en-US:official
You and Your Land Rover Discovery is probably the only text that even talks about doing LPG conversion.
Good luck.
Adam in NYC
