This is a slightly odd one: There is a variety of gas cylinders in use throughout Europe, in particular those in use in Britain are probably unlike any other (the fittings). Some 7-8 years ago I was in a motorhome on the continent and was directed to a depot just outside Luxembourg city where they actually simply filled my cylinders. Unfortunately I haver completely forgotten the exact location and/or its name. Does anyone know where the place is ?
If you are talking about propane cylinders, I think that the connections are now universal. The last time I was in Europe, it seemed to me that most of the petrol stations also carry propane. In any case you should be able to look in any phone book that lists companies and find a large number of facilities that fill them.
The last I knew UK propane has female fittings whereas elsewhere in Europe has male fittings on the cylinders - has the system been changed in the UK (in which case I know no evidence of it) ? Other countries have not adopted the UK standard. This is on top of the cylinder sizes and shapes varying quite a bit. The telephone books and/or yellow pages or equivalents generally only list EXCHANGE firms where you hand in your empty and take a full one for which you pay (contents). My question has to do with getting a specific cylinder FILLED, not exchanged for a different full one. This for Luxembourg, not the UK.