If he had left the bike at WHF and walked back. That would have possibly helped him at trial, as the prosecutions narrative was he used the bike. It would also contradict Julie's claim of him planning to use the bike. Of course prosecution would then say he cycled there and walked back.
He could have walked there and back. There is a source in one of the books that Nevill says after a family argument " Jeremy will walk it off, don't worry. Seems that Jeremy if in a strop would get to his feet and walk miles home if they'd had been out at a family get together. He was also 24 and reasonably fit.