The devil is often in the detail, and in this case, I would say that he took them to LA for all 6 seasons of "Lucifer" (TV show).
The offence you were convicted of is failing to provide information regarding the driver's identity, contrary to s. 172(3) RTA 1988. Nothing to do with failing to provide documents.
Also, there is no such thing as a civil charge (or in any meaningful sense a police charge). There are civil matters - which magistrates have very little involvement in, and criminal charges - all of which are heard (initially at least) in magistrates' courts. Speeding and s. 172 are both summary offences -
which means that they can only be heard in a magistrates' court (except on appeal or other more convoluted circumstances).
The normal process is that (alleged) speeding offence is recorded. NIP is sent to Registered Keeper with requirement under s. 172 to name driver. If RK was driver, and names himself offer of course or fixed penalty or SJPN for the alleged speeding offence issued to him (depending on alleged speed and limit). If he nominates another driver, NIP is sent to them, etc. until the driver receives NIP and names himself as driver and is issued offer of course or fixed penalty or SJPN for the speeding offence.
Where an s. 172 requirement (invariably included in the NIP) is properly posted to a person's last known address by first class post, it is deemed to have been served 2 working days later unless the contrary is proven. Once it is [deemed] served, the 27 days (28 days beginning with date of service) to provide the required information starts. Failure to provide the required information within the 27 days is an offence, subject to any applicable statutory defences - e.g. if it was not reasonably practicable to provide the information (which if the information was not provided because you were not aware of the requirement would include consideration of whether it would have been reasonably practicable to ensure that any such notice was brought to your attention - e.g. if the RK was working away from home for an extended period he might be expected to make arrangements for post to be forwarded or otherwise dealt with in his absence).
Ignoring all the gibberish, you have told us that it is a lease car, and presumably this means that you are not the RK. The first obvious question is what address the NIP you didn't receive was sent to. Was it sent to your current address? Was it sent to a previous address (and if so, did you update your address details with the relevant person)? Or was it sent to an "incorrect" address?