Streetview shows the same signs have been there since at least October 2008. The yellow sign on the left 'no cars permitted on bridge at any time' suggests that the minimum weight restriction is to allow delivery and service vehicles to use it but not cars, though it's a very unusual way to sign it.
As far as I can see there is no maximum weight restriction.
I think Mr 7.5 tonner knew best after all.
We have one of the remaining 4 ‘Bridge Chapels’, in the country, in WakefieldYet another bike on St. Ives Bridge pic, this time with another bike about to be on it
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Bridge over Clapham Beck, N Yorks. You can see the right bank end of the smaller bridge upstream.
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