Legal requirement or not?

If the purchaser made rewiring a property a condition of purchase, the seller would have decider whether that was worth it, especially in a seller's market.

There would probably need to be a somewhat convoluted provision inserted into the contract of sale as well. After all, what if the buyer decided he didn't care for the workmanship (or something)?

Exactly - a contractual agreement between the parties. Whether the wiring regs are retrospective or not has little to do with it.

It may be not as convoluted as a situation I heard about where the previous owner transferred a half share of the property to her daughter. When the property went on the market, the purchaser demanded indemnity insurance to cover the eventuality that the mother was declared insolvent, the transfer (to the daughter) was annulled and her 50% share became part of the mother's assets in the insolvency. They told the purchaser to piss off and sold the property to someone else three days later.

I wonder if that's lawyers on an hourly rate making up work for themselves? I can't imagine that is something any buyer would ever come up with.

(I don't think the lawyers are allowed to be on commission with the insurance company, but not certain)

Theo

Lawyers can and do make cockups that costs their insurers millions. Their professional competence is deigned to nitpick everything that could trip them up so any paperwork is legally bombproof.

I was amazed to discover, for example, that my ex wife of mow some years ago was still registered as having a beneficial interest in the house, despite having been paid a shitload to f*ck right off.

Fortunately my current lawyer managed to sort that out with a copy of the decree absolute

Hence the reason why these little 'what ifs' are often covered by a separate insurance policy as a matter of course.