Free Traffic Legal Advice

Please release your Google account as it is set at private and nobody can see your links.

Are you the driver, or is this a "disaster in the making" because you have only just discovered these documents and are the owner of the vehicle ? 

If you have not responded to the PCN within the period allowed, then you have lost the option to submit representations, and the only option open to you is to pay the sum demanded.

The PCN is dated 24th July and you had 28 days to either pay or submit representations.  So you are well past that period.
When did you actually receive the PCN ? The CC is dated 2nd September, and again, you are well past the 14 day period to pay.

I received it about a week ago with a bunch of letters

Sorry, but you'll have to be more forthcoming on why you have only just received these documents. Were you abroad or what ?

Reason to ask is that the next stage is the debt is registered at TEC (Traffic Enforcement Centre), and Transport for London will send you an Order for Recovery, which adds £10 to the amount. At this OfR stage, you can submit a Witness Statement, and get the matter reverted to the original PCN.  You can then pay it or submit representations.  Your circumstances for a Witness Statement would seem to be that you did not receive the PCN within the time allowed for you to respond to it, as you've only received the PCN and the CC recently.

I am the registered keeper.

I was abroad due to a family member's funeral and arrived on 26th July. Unfortunately, I was grieving so was not in the headspace to deal with many things. The letters were also delivered to an old address, which is where the car is registered too.

Around 8 months