OP, if you assert that you parked once only then the 'second' PCN is a shoo-in cancellation: 'penalty exceeded the amount applicable in the circumstances of the case'.
Why?
PCN 1 - not seen, but issued by CEO L601 at 11.13, it says so in the NTO;
PCN 2 - you've posted which carries the all-important 'first seen' time of 11.07.
It therefore follows that PCN2 is unlawful because a PCN had already been served at 11.13! You cannot start obs for PCN2, then issue a different PCN at 11.13 and then issue another at 11.17.
So, PCN2- the original subject of this thread is effectively dead, you just have to submit reps as above.
So, what about PCN1? I would suggest similar grounds.
Perhaps...
Dear Sir,
PCNs ********* (PCN1) and *********(PCN2)
I refer to the above issued, according to the authority, by the same CEO(L601) as follows:
PCN1 - 11.13. I did not find this on my car neither is it in evidence in the
CEO's photos of PCN2.
PCN2 - Issued at 11.17 but first observed at 11.07.
I am making formal representations in respect of both on the grounds that the penalty exceeded the amount applicable in the circumstances of the case, circumstances which are evidenced by the authority's NTOs.
In respect of PCN2, the authority are claiming that CEO L601 observed the car at 11.07 then at 11.13 decided to issue a different PCN(PCN1) for £130 for a separate and parallel reason(my car was parked once only) while still observing my car for PCN2 and then at 11.17 decided to issue this PCN at 11.17.
So, PCN ********* (PCN2) issued at 11.17 must be cancelled because only 4 minutes prior the CEO had issued PCN*********(PCN1) for the same contravention.
And PCN1 must be cancelled because the CEO only formed their belief that a penalty was payable at 11.17, 4 minutes after the penalty was demanded.
Perhaps the authority are able to work out what CEO L601 was doing, but as far as both PCNs are concerned and your demands for penalties from me I suggest that a veil is drawn over the events and that by return you confirm their cancellation.