Claytons yard was situated between Stone Street bridge and Oldbury Junction, that's it on P41 in Philip Weaver's book looking North East from beneath Stone Street Bridge. Just beyond the footbridge in the distance is Oldbury Junction. The Gloster has come from Spon Lane Junction - beyond that footbridge. The picture of the same location is in the lower image on P41 looking the same way (believe it or not!). Empty and sterile.
Sorry Victor - when they incorrectly turn left into the Titford Canal, they are turning South towards Titford Pools - dead end. When they back-track and turn left at Oldbury Junction they are heading West Nor West towards Tipton Junction and Wolverhampton - the WRONG way!
But that's the film makers continuity for you - non existent. All they want are 'scenes' at 'locations', it's all about the story and not the geography. Birmingham is in effect BEHIND them, and off to the East S. East as the crow flies.
Where Claytons yard used to be is now beneath the M5, which at the time of filming had not been built. Claytons boats ceased transporting goods in 1966, around the time of the filming, hence the derelict state of boats thereabouts.
Not as clear as I'd like I'm afraid. Click on the image to enlarge.