The mains electric and gas system have entirely separate control systems, so it a coincidence if neither are working.
The mains element in the C2 should have a cold Dc resistance of about 11 to 13 Ohms.
When were the caravans gas appliances last serviced?
You should always have gas appliances installed, serviced, removed and repaired by a competent person with access to all the necessary gas testing equipment.