I think the summary is
Jeremy said he got it from his mother for Julie to use
Julie admitted in her statement that in the past she had said it might be useful .
There was NO forensic evidence to show he rode the bike in the dark across fields and paths
Because there were no witnesses to him leaving home , arriving at the farm , leaving the farm , arriving home , then the method of transport is nothing than an assumption of something that could fit the timings . Nothing more , nothing less.