Not sure if anyone else has encountered an HGV on the railway bridge - it is a pretty daunting experience ! I wonder if they are allowed to go this way - the bridge is a Weak Bridge 7.5 tons.
I have done some further work on this problem and hopefully we should not be seeing any more lorries on the railway bridge. Apparently, there was some misunderstanding on the subject of what classes of vehicles are permitted to use the bridge. It has been clarified that the only overweight vehicles permitted are agricultural motor vehicles/machinery, as defined under Regulation 3 of the Motor Vehicles (Construction & Use) Regulations 1986; which does not include lorries.
As so often happens, the real problem has turned out to be a misunderstanding rather than an actual *problem*.