If you are going to be using your van abroad for any serious length of time, i.e. 90-180 days/year x 10-15 years, you should definitely consider refillable bottles as
@Breeze1 suggests.
@LindaRothwell has already been ripped off, some of that cost could have gone towards installing refillable.
I had a Gaslow installation, two cylinders with an automatic changeover regulator. It really was fit and forget, all you have to do is fill with lpg wherever you find it (which is quite common in Europe) and you don't have to worry about incompatible cylinders etc.
As you have already found, there are lots of variants in the U.K. then add in France, Spain, Germany, Italy, Greece, Poland, etc., etc.
I have no connection with Gaslow and there are other refillable suppliers, including lightweight bottles.