I received a PCN for 50r Performing a prohibited Right turn.
The no right turn sign was placed to the LEFT of the traffic lights

In my experience, signs to the left of a traffic light usually mean nNo Left turn - equally on the right of traffic light are for No Rigtht Turn. I saw the sign but did not focus on it as I presumed it was a No Left Turn Sign.
Indeed, the Traffic Signs Manual/Chapter 3/2008/4 states clearly:
4.12 The "turn left" and "turn right" signs to diagram 606 should be mounted on the left or the right of the signal head respectively. The "ahead only" sign should be mounted on the carriageway side of the signal.
The "no left turn" and "no right turn" signs should be mounted on the left or the right of the signal head respectively. Alternatively the signs may be mounted immediately below the green aspect. The government booklet "Know your traffic signs (Driving Skills), Great Britain: Department for Transport" has this illustration to reinforce the point.
I think this is pretty clear, which - to me - means that a No Right Turn sign on the LEFT of traffic lights in non-compliant and, therefore unenforceable...
Any thoughts, please?