Good to see you got it insured Mike.
Re their advice that it's an honesty system, when I insured mine a while back with another company that also had a limitation on use I was told that in the event of a claim the insured's version of usage would be verified with workmates, car club members, housemates, relatives, partners etc.
My experience with insurance companies and their investigators, albeit limited, is that if the claim is significant they will go to considerable lengths to see if there are reasons upon which the claim could be questioned. Just saying...