Help with regulators please

Your caravan is fitted with a bulkhead mounted regulator, you have in your hand the bottle end of the reg to bottle hose.

this is know as a POL 'propane' hose 'bullet' fitting, which fits a std Calor bottle.

If your 'spare' bottle is Butane, you will need an adaptor like this to fit it.

I would get rid of the butane bottle and get a propane one. propane burns hotter than butane and has a much lower freezing point which helps if you intend to do some winter touring.

Good point above, but, if you want to, you can use your remaining butane gas with the adaptor I linked and then, when empty, exchange for a full propane one....

as it happens, the weather has been positively 'Tropical' here the past two days, no trouble burning either gas.....

has our two day 'winter' been and gone?....two days more than we normally get in the soft south...