You make reps now as you have the PCN. These are known as informal reps.
The importance of the registered keeper is that should the council reject these they would pursue the penalty by issuing a Notice to Owner to the registered keeper, so obviously who is the RK and their DVLA address are important.
IMO, your grounds would be penalty exceeded the amount applicable in the circumstances of the case and procedural impropriety.
Dear Sir,
PCN ********
I am making representations against this penalty on the following grounds:
Penalty exceeded the amount applicable in the circumstances of the case;
Procedural impropriety.
The CEO believed that a contravention occurred and issued a Penalty Charge Notice. For the purposes of these representations, it is not necessary to address the contravention because this is not germane to the procedural errors within the PCN itself which flow from the stated parking contravention description which is:
'Parked in a residents’ or shared use parking place or zone without a valid virtual permit or clearly displaying a valid physical permit or voucher or'
I enclose a copy of the PCN for reference.
Also stated below is the description which has been mandated by the Mayor of London - and therefore the only form permitted to be used - for the alleged contravention:
Parked in a residents’ or shared use parking place or zone without a valid virtual permit or clearly displaying a valid physical permit or voucher or pay and display ticket issued for that place where required, or without payment of the parking charge
For convenience, I have highlighted that part of the permitted description which has been omitted in my PCN.
To demand a penalty for this alleged contravention without using the description mandated by the Mayor of London and the London Councils joint committee is a procedural impropriety(a); and as the description is not mandated then the penalty demanded is not prescribed and the penalty itself exceeds the amount applicable in the circumstances of the case(which was £zero).
The PCN must be cancelled.
(a) From the General Regulations
Setting the levels of charges applicable in Greater London
24.—(1) The functions conferred on the London local authorities by Part 2 of Schedule 9 to the TMA 2004 (charges applicable in Greater London) in relation to parking contraventions committed on or after the commencement date are to be exercised by those authorities jointly by means of the single joint committee set up in pursuance of regulation 18 (“the Joint Committee”).
