I've found it harder to get gas when I'm up in Dundee - the one (hellishly expensive) Shell garage in Arbroath has stopped doing it, and the big Asda at Kingsway East has stopped doing it as they switched to an unattended filling station.
There's only the Shell garage on Forfar Road left doing it but because they're EuroGarages they have no plans to get rid, apparently! Good thing too, because even at 64p/l they're still better than nothing.
What I have noticed is that with Shell stopping Autogas, they've switched to Avanti and the pumps are labelled up as "Avanti Propane". Now I don't know if that's straight propane as opposed to an LPG blend - I expect it is - but what I have noticed is that my tired old quarter of a million mile 4.0 goes like particularly dry shit off a teflon shovel on it, compared to the stuff I get at Morrison's.
As for the 80% shutoff valve, mine only worked for about six months and then failed, and now I just kind of go by the idea that if it's empty it'll take about 80 litres, same as when the valve was working. Is there any downside to this? I guess I shouldn't just keep pumping until the numbers stop going up...