Cant fault the prosecution for using the sea wall theory and I can see why they did even though I dont believe so.
Via the road route, Walk, car, or cycle I dont believe personally he would have been identified. I would wager probably 98 percent of people would have been in bed at the material time. I dont believe nobody would have rushed to the window to see the car leave etc etc. But in terms of visual on the chance he was. Being on foot or cycling offers more chance of a positive ID than the car.
The biggest risk for him would have been a police patrol car clocking him while they were on duty. A man out at that time is seen by the police as being up to no good.
Other than that only foxes or cats would have clocked him.