To be able to charge the leisure battery as you are driving in the Delta you must do the following:
Switch the panel on the Delta ON (next to the numerical panel indicating battery voltage level)
Battery Charger - ON
battery should be put on Leisure battery setting.
Please note for the fridge to work you must have the interior dial switched on
For the plug sockets to work you must be plugged into the mains and ensure the trip switches (right of the plug sockets above battery charger button) are all up.
If you are still having issues please check the fuses to see if any have blown. If so these can be found at any petrol station which should solve your issue.