Hi Russ - have a quick look at that thread noted above - I put in some notes about price etc. - about £2K +vat though.Problem wise, I've had only 2 - first one was i didn't clamp the filler on properly once and trapped the little plastic cord that holds the filler cap when it's open - when I released the filler it had sliced the cord in 2 and the cap dropped to the floor! Hardly an issue, as long as you remember to pick it up after refilling!
The second one was I picked up a batch of dodgy lpg somewhere which had some gunk in it that clogged the fuel line so from cold it sometimes used to flick back to petrol thinking it had run out. When it warmed up it was fine. The installer cleared it from the pipe for me FOC during a check up though so all fine.
I do have a slight issue becuase my ECU isn't quite set right as it's a South African one, but that won't affect anyone other than me! Doesn't mean anything in practice, just need to get it tweaked at some point. Fuel econ and performance is just fine.