I sold a tyre on Ebay. The buyer's address on the email from Ebay was his old address.

I sent it about 3 or so weeks ago by recorded delivery and put my return address on it.

On track and trace it just says could not be delivered, returning to sender. How long should this take?

This may help

mandog – we had a similar thing happen where receiver didn't sign for it and it came back to us, it did take quite some time (weeks) to get back to us, worth giving Royal Mail a call as they maybe able to provide more tracking details than that shown on-line that's what we did.

I have to say that of all the crap things about Recorded Delivery (we posties hate it BTW) the crappest is the fact that if the receiver cant sign for it/cant collect within the week it gets immediatly returned through the system. With other services, even good ones like Special Delivery, you get three weeks.
I've had a few packets of my own sent back, 'cos I couldn't get to collect them, whereas if they'd been sent standard packets there would've been no problem (and probably no less secure)
Sorry, this isn't answering your Q, Just my mini-rant 🙄

I'll try calling them tomorrow