You should find a copy of the RM6271 manual here,
www.manualslib.com
I have looked through the document, For the gas igniter to work, it does need a permanent 12V low current feed for the reignitor, , which should connect
positive to the violet and
0 volts to the black wire on top of the fridge.
There is no 12V fuse for the ignitor in the fridge's circuitry.
Check your voltages at the connector on top of the fridge.
Without a detailed knowledge of the wiring design of your caravan, I can't tell you where there might be a fuse, but usually its controlled by the caravans power distribution centre.