This is not uncommon now Neil. When you renew you probably go for quotes to try and get better pricing. They will specifically ask you if you have ever had insurance cancelled, denied or refused for this very reason. As always saying the wrong thing means your new premium is illegal and if ever tested will be cancelled. This leaves you in a deep pit.
"cancelled, denied or refused" - might not be the same as this situation.
The policy is being allowed to run until renewal, so it is not cancelled. Upon renewal, the insured parties will no longer meet that insurer's underwriting criteria. That's no different to Admiral declining to cover my modified Defender or Hiscox declining to cover a 17 year-old. These are commercial decisions based on how different insurers select their cohort risk.
