Hi,
If you have a low pressure system (regulator on bottle) then simply remove the low pressure T valve and connect the low pressure outlet directly to the caravan.
If you have a high pressure system, with bulkhead mounted regulator, then you have several possibilities:
1. Just use the rig as it is with the high pressure T valve set to the bottle. This has the possibility of a leak out of the loose pigtail - but these high pressure pigtails on a switch over system should have non-return valves in the pigtails - check if yours do...
2. I'd be happiest with the T valve removed, and the bottle pigtail screwed into the regulator. This is the best and safest solution...
If you have any doubts about doing any of this work yourself, seek professional help.
Robert