Not sure the location on the PCN is correct (although not sure if it's wrong enough to invalidate it either).
The box junction concerned is at the junction of Lea Bridge Road and Church Road.
I can't find any road called Markhouse Corner - there is a box junction at the junction of Lea Bridge Road and Markhouse Road but it's not the one your vehicle stopped in (that's the other one visible in the footage a few metres further ahead).