LPG issue

I've got a problem with my LPG system. Initially it would switch back to petrol whilst running on LPG if I booted it a bit ie joining a motorway, giving a beeping sound until I pushed the button, it wouldn't allow me to attempt to switch back to gas unless I switched the ignition off, then back on again. Now it's got worse and 80% of the time it just won't switch to gas at all, the lights flash as if it's preparing to switch from petrol but it rarely does. It's happened at a time when it's my only car, I'm due to drive to Southampton next week from Canterbury, I don't want to do the whole round trip of petrol alone and I'm not sure if I'll get chance for the car to be in for repairs unless I can find someone who knows what they're doing with it and also open on Saturday. Is there anything I can check or do in the mean time? Any help appreciated. Cheers

This normally happens when the gas pressure is low or the tank level is low...

I'd be mindfull to check/change the LPG filters as when they clog, gas pressure to the injectors reduces causing it to think there is little/no gas and so changes back to petrol!

I'd suggest the filter too. Apparently they're supposed to be changed every year...

Could be overdue then.

I had the same problem and it was a duff sensor.

Ok cheers. Think I'll need to get the whole system checked though finding a local specialist doesn't seem to be easy.