Hi Mark,
It may not be quite as simple as Rober is sugegsting. It all depdends on what standard your carvan was constructed too
Many older German caravans used a 50mB gas pressure. This was controlled by the regulator that was fitted to the gas bottle. The operating output pressure will be on the regulator. If your is this type, the you will need to source 50mB propane regulators to fit UK bottles. Calor and Truma gas used to offer such regulators.
You may have younger 30mB regulators, in which case it is a relatively simple job to relapce the with UK 30mB regulators.
If you have the latest standard, the regulator is fitted to a bulk head, and the high pressure gas is connected to it through 'pigtales' It is easy to obtain the necessary pig tales to suit UK bottles.
As ever, if you are in any doubt arrange to have your system checked by a competent gas fitter, who can advise you more accurately and safely than this forum