Yes just walk away and look at it as they have had a rent free property. Seems the bank puts on massive charges for arrears so they just can’t win. I doubt they would chase but even if they do they have to sell the place first to prove how much loss they were hit for. By the time it is sold they could have well covered their tracks. Those surcharges the spanish banks put on for arrears would count as unfair terms and conditions in a UK court, would be thrown out….unless they are planning to stay in Spain?