Windsor Road width restriction

Windsor Road has a narrow section near its junction with Histon Road. This is supported by a traffic regulation order, the Cambridgeshire County Council (Windsor Road, Cambridge) (Width Restriction) Order 2006 , which bans vehicles over two metres wide from a ten-metre stretch of the road that coincides with the narrowing. What's odd about this is not the restriction itself, but how it is signed.

On Huntingdon Road, on the approach to Oxford Road, there are two signs apparently warning of the width restriction. They appear to be width restriction signs to diagram 629 with distance plates to diagram 573. This is not a prescribed combination – in general diagrams 572 and 573 may only be used with warning and informatory signs because regulatory signs are only placed where the restriction actually begins. There are also the small matters that the restriction is 700 yards from Huntingdon Road and that TSRGD requires short distances to be expressed to the nearest ten yards.

The correct sign for this circumstance is diagram 818.3, which can be varied to show the required information.

Closer in, at the north-east end of Oxford Road, there's a similar combination of signs, with the same problems.

The approach from Histon Road is similar, but here the plates have an additional arrow pointing down Akeman Street. This is not a prescribed variation for diagram 573 (or 818.3), but that shouldn't be a problem since I haven't found any order establishing a width restriction on Akeman Street anyway.

On Windsor Road itself, there are signs about 70 metres from each end of the restricted section: one to diagram 629 (without a plate) and one to diagram 517 (road narrows on one side). The sign to diagram 629 is wrong (again) since it should be at the start of the restriction, rather than 70 metres away. The proper sign to give advance warning of the width restriction would be another variant of diagram 818.3 (placed below the triangular sign rather than above it). The eastern sign is particularly silly, as it purports to ban wide vehicles from access to the Co-op's loading bay.

Finally, where the width restriction actually applies, there are no signs to diagram 629 at all, whereas there should be at least one at each end. There are strange miniature versions of diagram 515 (about half the smallest prescribed size) though.