Here are most of the LPG stations in the UK, you can download them onto a Satnav as well. I havent heard of any LPG stations shutting down other than petrol stations which have gone bust or closed for maintanance. I travel exstensivly througout the UK and have never been caught not being able to fill up with LPG.
Most of the large brands are opening new LPG pumps on a weekly bassis.
Dontforget you still have petrol in emergency and gthe systems use petrol to start up with from cold in the mornings.
You soon learn where your LPG statrkions are.
Heres a link http://www.mylpg.eu/stations/united-kingdom
I live in the country, Hampshire and fill up at a Calor Gas depot I pay 65p a litre I always have a big smile on my face when filling and driving.
Good luck. Mike