Their own photos shows obscuration of the sign by the scaffolding yet still they issue a PCN. So why do they do this ? Because they are a venal and rapacious London council !
So I would submit reps based on the sign being obscured, and there being no sign on the other side of the street, so you saw no restriction sign on approach to the junction. In addition, there is no direction indication in the form of arrows in the carriageway, the restriction is indicated by the obscured sign alone.
If you like, post up a draft here for review before submitting it.