I've got an interesting little problem with the NHS. I have just completed a year as a participant in a research project and as a "thank you" they have given me a £10 gift voucher.

I don't want it. I would have preferred it if the NHS kept the money. I was aware there was some token payment but there was no opportunity early on to say I didn't want it but had naively assumed I could refuse it when they handed it over. But they had already spent the money on the voucher, so refusing it doesn't save the NHS any money. In any case, I participated because I thought the research worth while, not for money.

I could perhaps give them £10 cash somehow. But I imagine the staff costs of handling it would be more than £10.

There are charities, of course, which could take the money efficiently, but that doesn't actually put in the NHS as such.

So: any ideas how I could get as much as possible of it back where it came from?