motorhome fire damage

hi, i have had my motorhome damaged by fire at  Charltons Lynemouth caravan storage site this weekend.

Charltons tell me that they do not have any insurance to cover the damage to my motorhome and that i must claim off my own insurance, 

does anyone know if this is correct,they have a CaSSOA Gold certificate and i thought i would be covered by this, can anyone help please.