Keep looking. The fact that you have some lights working rules out many problems.
Some caravans have fuses next to the the incoming battery power but also have a secondary set for localised items. Look behind, under or near any switch or volt meter panel for some more fuses,
Failing that, go round a caravan site and find a similar one- Take a bottle of wine with you. It always works
CC member18017873, August 2012