I have recently received a penalty notice for stopping in a box
junction on a busy London road intersection. I recognise that I did
stop in the box junction, for some time, and probably blocked the
crossing traffic, and I intend to pay the fine.

I have reviewed the thread on "Bus Lane Penalties" and noticed that
where (temporary) bus lanes are not legally registered, bus lane
penalties can be avoided. As a matter of legal interest, I am
wondering whether there are any similar legal loopholes with respect
to box junction penalties? For example, the road in question is
reasonably well worn, and I am wondering whether there are any
requirements around the painting on the box junctions? Or, as with
recent speed camera loopholes, are there any specific requirements for
the signs associated with box junctions?

Robin