Where criminal liability actually starts
This is the point most often got wrong in both directions. A breach of planning control — unauthorised work, an unsatisfied condition — is not in itself a criminal offence, so nobody is going to prosecute you for buying a house with one.
Non-compliance with a notice served to deal with the breach is a different matter and does carry criminal liability. The sequence is: breach, then notice, then a period to comply, then an offence. Declining insurance does not put you anywhere near the end of that sequence on day one. It means that if the sequence starts, you fund all of it.