Anybody driving a car that has been converted to LPG? Advice needed

Recently started driving one - a Jaguar XJ6 - company car, not private. I was just wondering what the economy figures might be. I have been driving a BMW diesel and getting really good mpg. I don't want to be out of pocket. So far the Jag uses a tiny bit of petrol to start up but then clicks over to the gas and I have been buying it at about 77p a litre. Obviously that is significantly cheaper than diesel but it won't be if it does about 20-30 miles to the gallon. I am a very high mileage driver, doing between 4 and 5,000 miles per month.

Any hints, tips and information that anyone cares to pass on would be welcomed

 

Hi mate, we had a Rover 75 LPG conversion, the mpg on gas was about 1 mpg worse on gas than petrol, the gas was just about half the cost of petrol , so we were getting just short of double the miles for the same money, worked out very economical for us.
What engine has the Jag got?

 

It's a 3 litre petrol engine and, so far, it is using virtually no petrol but I seem to be topping up the gas a lot. Very early days yet but hard to tell how it will turn out

 

Rather than use LPG why not ask thereev to blow his hot air into your fuel tank.