As a little update, having lived with the LPG conversion for about 9 months I can safely say the following
1) I would NOT recommend warrington autogas for a conversion. My slightly unusual car was enough to completely fox them and require many trips back to get it running right. Possibly they have no trouble with standard 1.6 focuses and normal astras, but one slightly different (and my engine isnt even that unusual) car like mine and there was no end of problems.
2) If Warrington Autogas are the best of a bad bunch, I hate to think what the worst of the bunch are like.
After repeated trips to Warrington Autogas I still have the following:
A) Lumpy idling. This does not happen on petrol.
B) Intermittent stalling. Every now and then you'll just coast up to a junction and find you have to restart your engine, again, doesnt happen on petrol.C) A gauge which is neither use nor ornament. All indications of remaining LPG are to be done through the trip counter. Repeated attempts to have this fixed bore no fruit whatsoever. Not only that, the gauge wasnt glued down, so comes loose, that will be another job for me to fix in time.
D) The car is still dropping water somewhere. It wasnt doing this before the conversion, so again this is another job i will have to fix.
3) In all honesty, bearing in mind Warrington Autogas were given repeated attempts at fixing my car, they really should have been taken to court for their poor workmanship. All I had in way of compensation was one lousy free tank of gas, which they tried to charge me for anyway before i argued with them.
Andy and the guys at Warrington Autogas are lovely blokes, but there are lots of lovely blokes around, few of whom I would trust to perform extensive and complicated work on the fuel system of my car. Andy and his colleagues are now firmly in that group.
Look at the engine bay after the install.
Note the gas distribution block not secured in any way and free to roam the engine bay.