I just tried to buy home insurance and was told that because I had a couple of convictions years ago for smoking pot on my criminal record, they couldn't (or wouldn't) insure me. Haven't I done my time and paid my "debt to society"?
You did the right thing by disclosing the convictions.
This is consistent with the duty of complete good faith that an insured (or a would-be insured) owes to their insurer.
In short - they are not obliged to deal with you if they don't want to.