16-12-2020 8:50 AM
As your listing states you won't accept payment except by PayPal, you are on shaky ground as once paid the buyer can get their money back and you lose the high ticket bike.
Cash on collection is the only safe way.
Unless the buyer you talk about is willing to bring cash and you trust them by putting a best offer on the listing, you should block them..
Be careful. Could be a Hacked Account, there are awful lot of them about. Do as @plpmr advises.