For the UK, go to Richards site, www.filllpg.co.uk
, For Europe try here http://www.gas-tankstellen.de/menu.php?jump=download
(go to the bottom of the page and use the Google translate drop down to change it to English).
France is never a problem, all motorway services and most of the supermarkets sell it. Belgium has plenty of stations and is cheaper than France (and UK) and Holland has plenty of stations and uses the same filler as us. My experience with Germany was about 1 in 3 motorway station have LPG, so not as good as the other countries and you'll also need an Acme screw thread adapter (you'll need that in parts of Belgium too although some stations have different fillers on different pumps, Italian cup and another, either Acme or bayonet). You won't need a PIO file for Poland, every filling station sells it along with most farmhouses too. In Poland you are never more than a couple of miles away from a source of GPL!