brooksby wrote: ... Is there a definition in law of "for access"?
If there is, I think it will be in the form of decided cases ie appeals usually by way of "case stated" to the Queen's Bench Division of the High Court. If so, it will be in (expensive) text books such as Wilkinson's. I've looked at the usual internet sources and I can't see anything other than when that supplementary plate may be used.
I think the short answer is that it will depend on the wording of the TRO which will be specific to that site depending on the circumstances. I think, for instance, that if there are legitimate destinations along the "no vehicles street" the TRO will list them.
I can't speak for other parts of the world but I don't remember much police enforcement: it's one of those cases where the highway authority tries to do something and it's only sporadically enforced if at all. No enforcement tends to mean no appeals. The situation is complicated by the flying motorbike being one of the most widely misunderstood signs on our roads.
This is now becoming more of an issue with the increase of situations like the one in your streetview where highway authorities are trying to keep private vehicles out of shopping centres and off bus routes. Some of the enforcement has now been decriminalised and passed to highway authorities in a similar way to the enforcement of yellow line parking and cameras are being used, much to the disgruntlement of the "can't touch you for it" faction. The main point is that as it's decriminalised, "innocent till proven guilty doesn't" apply. Once a penalty notice has been issued, the process inexorably trundles on until payment is received, the recipient of the notice successfully appeals or the bailiffs are instructed. There have been some well-publicised appeals which have been discussed on here, based on the confusion caused by the signs. I've not looked into it closely but it would be easy to conclude that the appeals tribunal (I can't remember the correct name) finds the flying motorbike sign confusing.