D'oh! Nationwide Mortgage

I would expect that if you contact Nationwide and explain that you made a mistake they would be happy to return the 100 overpayment to you. It's situations like this that make you appreciate the difference between banks and building societies.

Don't panic - if you read the small print I think you'll find the penalty is 3% of the amount you overpaid, not the entire mortgage!

Is that so?! I never really felt the urge to understand that clause of the agreement when I read it because I thought I would probably never be in the position to have to worry about it!

So you reckon I would be "charged" a redemption penalty of 3 had I not asked them very nicely the next day to refund the money I accidentally overpaid? And consequently my outstanding mortgage balance would have decreased by 97? Well if that is the case, indeed there would have been nothing to worry about. And since they are issuing a cheque and the time (and money) wasted in phone calls and lost interest, by the time the cheque comes and is paid in and is cleared etc, 3 would have been lost anyway! Nevermind!

Probably. But it might be 3% of the total overpayment, ie including the permitted penalty free part, so if you paid 600 and the permitted overpayment was 500 they might charge 3% of 600. ISTR the small print in mine didn't make this totally clear when I had a tracker with Nationwide.