As there seem to be a lot of people who buy here in Spain whilst living in the UK, and pay mortgages etc, I though this was worth passing on.
A colleague of my husbands recently had her bank account frozen as her NIE had expired and she had not informed them of the new number…mainly as she had not had time to renew it! Luckily this was not the account that she was paid into but you can imagine the problems this could cause if an account you used to pay your mortgage etc from, whilst in the UK, was frozen. So just a warning to note when your NIE expires and remember to renew it when the time comes!!