No one is going to be awoken by a car engine or a car driving away.
No one is going to be window watching at 2am
Nobody is going to ID Bamber in his car whether they are a pedestrian or in a vehicle travelling in the opposite direction
Security cameras will not give a positive visual ID
Security cameras could ID the vehicle make. Too much of a coincidence if it's an Astra.
Awake residents of Head Street may hear a vehicle and look outside.
As you said, the car breaking down would incriminate him.
If he was going via Brook House Farm, he would cycle. Silent, invisible, 12 minutes, minimal energy, perfect terrain, options if the bike conks out.