Having looked at this myself some years ago, and more recently for a friend, you do get what you pay for. There are a number of cheap convertors around, but much of their work leaves a lot to be desired. Any RV with fuel injection and a modern OBD system needs a good conversion otherwise the RV will spend most of it's time in 'limp home' mode.
If you want a proper job by a guy who really knows his stuff and takes pride in the job, Steve Griffiths at Anglo American Autocare in Newport Gwent is the man.
He fitted a dual fuel LPG conversion to my Chevy Vortec RV. 6 years and 40,000 miles later I was still delighted with the job and it had easily paid for itself. First time I took the RV to a VOSA test centre for it's MOT they praised the quality and integrity of the LPG work.
my hurricane rv was fitted in wales also and i have had no problems whatsoever.it changes to gas in a few minutes and you dont know its changed,thought it was a bit pricy at first but its been worth every penny.i have 2x 110ltr tanks fitted but its fills with a very neat filler on the side next to the petrol filler, my engine is an 8.1 gm, hope this helps