No point contacting eBay as they will just see your listing does have an alternative to collection , that is, a £25 postage charge.
I have found of late when listing or relisting, to double, double check that postage option box as I too have had it jump sometimes from Postage only, to Postage AND collection in person.
All I can suggest , is to message the buyer explain there was an error / fault in listing, the item has only to be a Collection item.
Hopefully they will understand, and you can cancel the order citing ....Problem with Buyer's address. This will fully refund the buyer and your seller performance will not be affected.
If you do then relist the bike, as said, do a double check that the box for postage selected is Collection ONLY.
@666edd