Need some advice from people who know v8s

Hi
I have a discovery 2 4.0 v8 with lpg. It is a rest of world spec engine and i have been told its the low compression engine. I don't know much about these engines (as always owned diesels) and i cant seem to find much out on the Internet.
I know the previous owner last year had fitted a European spec ecu and lambda sensors to meet uk emissions (not too sure why as it had ran for the previous 5 yrs in the uk ok)

Its been having problems with lack of power on hills and misfire and stuttering at about 1200 - 1500rpm on petrol and lpg and after taking it to a lpg garage for a service he told me that the petrol ecu had 17 faults stored and that the O2 and EVAP emissions were not resetting. Thats all the information he gave me.

Any ideas what this means?

have a live data reading done what machine did they use on it?
it can be a mechanical issue or igintion issue with the engine.
was it the correct ecu has it been set up properly?

Regarding the ecu, i presume so. The only information i have that it was a secondhand ecu and it was reprogrammed for the car.
As for the rest i don't know, I'm down on the isle of wight and as far as i know there is no v8 specialists or anything near to me.