Thanks for the replies guys, I'll try to answer the questions..
Rumble, it's just a boggo white 2007 T350 145, Petrol & LPG dealer fit Necam. it's got a 4 digit plate that ends in 1 so that's the only give away.
I was thinking the BOA as it is already RWD for the oil pick up etc and exhaust etc may nearly fit, also shouldn't have a problem with emissions due to LPG anyway
Limited black, that's why I am trying to find out what I can before I do it, I don't think it will be done in a day but I do like the challenge, if it mates up to the std gearbox then the rest is relatively easy.
Clocks shouldn't really be a problem, I can always run the 2 ecu's side by side, the BOA engine management doesn't take much to start the engine, I can live without abs/a speedo (Tom Tom)/ rev counter in the short term if needed, just need it back on the road pretty soon.
Luke, Yes

will try and get a pre '92. I've seen 1 v8 Mk7 transit but it had a lot of work done and don't want to modify the firewall, not sure if that was the case as I have only seen the video. Can you point me to anyone that has done the conversion in a Mk6/7 please? Will I need an adapter plate as it is already petrol? can I buy one off the shelf anywhere? the engine was completely different in the mk6 to the mk7, I believe it is the ford ranger engine (unsure of what year).