On rallies and temporary holiday sites without EHU I have used a 13kg propane bottle standing outside the gas locker. I always thought that as long as it was stable and under 15 kg it was within the rules. Just left a THS with my bottle. Steward asked me if I knew the rules as he had just read that it might be against the rules. This was meant as enquiring rather criticism of me. I looked on the C and CC website and found that it probably is. It says if there is a good reason one up to 15 kg may be positioned outside as long as it strapped to the caravan etc. It cites the example of no gas locker. So by implication if you have a locker then no external bottles. It applies to all club events. It is apparently for safety reasons.