I too would like to know if there is actually a law, however Phil your sign off sentence copied above I find to be somewhat confusing as surely you ARE talking about standard OTC gas bottles that don't have built in 80% regulated cut offs being refilled at petrol stations?
Phil
No Phil, my thoughts have been about refilling a say 6kg propane non 80% compliant bottle from a larger Propane bottle in a private environment, I.e. Not in a public place.
I noted in my search for Rules and regulations that someone on ebay had been prosecuted for selling adapters that enabled people to do exactly what you are saying, filling non compliant tanks at autogas outlets. But I also noted that the prosecution was for selling items which were not up to standard and had a potential to leak in use, this prosecution was bought by Trading standards and although it was portrayed that the filling of bottles by private individuals was illegal practice, it was actually about a trading standards issue and nothing to do with the legality of filling your own non 80% bottles at an Autogas station. However as I say my search was for the actual white paper regulation about the filling of Propane or for that matter Butane bottles by non authorised persons? Which although I've spent quite a time searching I can not find anything that prohibits the practice. Phil.
P.s.
Once again I am not condoning the practice, but having done it myself 50years ago in a military situation through necessity and found it quite safe to do, if done correctly. I'd really like to know the truth of the matter. The prosecutions of people who have caused damage and accidents through filling their own bottles have been akin to someone with a valid driving licence being prosecuted by the Police for dangerous driving and not because they were driving per say.