Hi, I need someone's advice!

Months ago, a friend and I were given two tickets for the next month's "Evgeny Kissin in recital" at Barbican Hall (5th March), but unfortunately it has turned out that we cannot make it.

And so far we have found one person who wanted to go to the concert. But still we have one more ticket left.

We have no intention of selling it (since we didn't pay for the tickets ourselves). We just want to look for someone who would really love to see Evgeny Kissin, so that we could simply give the ticket to him/her to enjoy the concert.
But we don't quite know how and/or where we could find such a person.

Does anyone know any website that deals with this sort, or is it alright if I post a message somewhere on this forum, saying "A ticket to give away"?

Any help/advice appreciated - we really do not want this 45-quid ticket to be thrown into the bin...