i had a similar 'good will gesture' in argos when i returned a faulty DVD player... the one i returned cost me £40 11 months ago, and the equivalent DVD player in their current catalogue is £50, so they tried to charge me £10 to get a faulty DVD player replaced. cut a long story short, finally got the manager over, who stood his ground until I said I'd quite happily write to their head office about the matter, and i'll also point out that the manager, whom is called Paul has a name badge saying David (i used to work in the same store, so i know the jumped up little prick)... at that point i got a 'good will gesture', at which point i told him it's not good will, it's my consumer rights, and i may still write to your head office mate!