Thank you - it is very frustrating!!
My daughter (who I bought it for) has just checked the original listing - it says the phone is "bronze" when it's black, & also that the screen isn't scratched when it is (fitting with the battered state of the rest of the phone). And the flash doesn't work either, I'd forgotten she'd told me that.
I think he'd be hard pressed to claim that a phone which left him 3 weeks ago in a very battered condition was then in perfect working order but has stopped working since! He was careful to use the word since: "all functions were working correctly and so I was suprised to hear you have since had problems". It's highly unlikely that he'd have checked any of the mechanical functions IMO, let alone all of them.
He didn't reply to the Paypal dispute message, just to my original ebay message - that's odd, isn't it? Everything is timed so he can't pretend he hadn't had the Paypal message before he replied.
I have just sent him another ebay message with this additional information (asking if he's sent us the wrong phone ) & requesting a more reasonable response - if I don't get one I'll send the phone back recorded delivery, & then escalate to claim.
Thanks again for your advice, pf - I'll let you know how I get on!