if it was a quality based reason for moving it would be a very difficult thing to insure unless it was so bad a local authority had closed it - how would the underwriters work out the risk and what would the exclusions be? I've not heard of this cover, if you do find it I'd like to read the small print.

but if it was something like the property was closed (owners gone bust/banned by authority) and you couldn't get access it ought to be covered by the Supplier Failure Cover section of Independent Traveller policies which have started to appear. Sometimes SFC is available as an add on to other policies. There's a thread in the DIY forum about the latest John Lewis/ M&S/ Axa independent traveller policies, Saga also do it but at least one person in the party has to be over 50.

if the property didn't exist and you had been taken for a ride it would be a grey area and probably wouldn't be covered.

if you've paid by credit card or Visa debit you'd have some protection for your original payment but not consequential costs like replacement accomodation.