Nice one, I can relate as similar situation. First property involved a chain (probate where apparently, the owners were a bit keen to get their inheritance). The whole chain fell through so had walk away and start over. The mortgage offer expired but a phone call and all was well. At the time, it was a horrible feeling, the thought that the mortgage offer would change/withdrawn 6 months later (no idea why as circumstances had not changed) but still, its an extra stress as you know a deadline is looming. Best wishes for the move.