The letters from DCBL should indicate for whom they are operating.
If not, you should be able to find out who “enforces” the parking at your partner’s site.
You can send them a Subject Access Request to obtain the information they hold on you, including the parking charge notices.
You can also serve them with a formal notification of your current address, which they must use in future correspondence.
Just not DCBL in any way, ignore them at all times.
Once you receive the notices you can post here and we can advise - there is a good chance that you don’t owe them anything but without the information we can’t guess.
Please stop going on about your “DL”, by which I think you mean your driving licence. It contains no details about your car.