Keep or return desk?

First time posting on this board, I have a conundrum and hoping you all will be able to help!

I've just moved into a new house and am furnishing it. On the weekend I saw a desk a local charity shop. It's a really lovely piece (and I'm normally fussy about furniture), solid walnut with beautiful proportions. I thought it was a steal at £75 and bought it to use in my spare room/temporary home office. There was a delivery charge of £15.

Unfortunately, the house and I are still getting to know each other. It's an oddball old house with only a narrow spiral staircase leading up, and although bigger items have gone up successfully (which is why I assumed it would be no problem), it turned out that the desk was just exactly the wrong shape for it, and was never going to go up that way. Very frustrating, of course, but I was prepared to chalk it up to experience and either get the desk up through the window at a later date, or use it downstairs (I don't really *need* it there, but there are a few places it could plausibly go and be useful, and in due course it could be used in the home office shed I am hoping to put in next year).

Then, someone pointed out that charity shops do returns (at least, this one does). I have the receipt, so I could do that, although I would need to pay another £15 for them to collect it, as I don't drive and don't know anyone in the area I could ask for help, so effectively I would only be getting £60 back.

So, do I keep it or return it? As I see it, these are the arguments:

Keep it:
- It's a beautiful desk, extremely good price and would be useful eventually
- I feel a bit mean returning something to a charity shop without it being faulty

Return it:
- It's not serving its intended purpose and won't serve any necessary purpose for at least another year, so it's a waste of money no matter how you try to frame it

Help pls?