Do you agree his claim is very weak?
No, I don't.
Bamber states it would be left at the red lion pub.
He obviously knew the landlord
He also states that Julie could get the Osborne bus direct to Colchester.
I also believe the bike would be useful for Julie to get out and about while Bamber was at WHF in the day working before he could come to her when he finished
It's not farfetched or ludicrous. It's quite possible