After a look at the bridge in operation I now realise that it is a lift bridge, lifting to allow the canal traffic to pass. I do live in the area but am not a native, hence not overfamiliar & only taking in some of the history I come across from time to time.
I spoke to some locals & barge folk and it seems that there was a lift or turn bridge of sorts on the site since the days of your William Hill. I haven’t looked in any depth but there seems to be a lot on the internet related mainly to the modern structure.
Acknowledgements to Stan for the links to a great selection of photographs.
So although this may not be the spot it seems most likely.
Regards.
tc