Roymondo:
All the signs were knocked over? Or just the ones on the bridge itself? There are several advance warning signs on all major approach roads, plus a few more as you get further into the town.
The one coming down into the town from Melksham way so when you would get to the bridge you’re faced with no option to reverse and a right turn that looks like you could get stuck in an artic a lot choose to go over the bridge to find somewhere to turn and come back the way they came. I don’t know if the return makes two trips to trigger a fine but wouldn’t be surprised.
I’m fairly local and once missed the right turn coming from Staverton to go to Bath and had to cut through a residential area to avoid going further into the town when I realised what I’d done.