Use a Subject Access Request to Euro Car Parks to obtain all the personal information they hold on you, which will include the original Notice to Keeper you did not receive.
Ignore DCBL.
Come back when you get a Letter of Claim from
DCB Legal (not the same company). You will receive a country court claim in due course but hopefully by then you will have obtained the missing documents which may be helpful in constructing your defence.
You ask about similar situations; search the forum and you will find many, including
https://www.ftla.uk/private-parking-tickets/eurocarpark-overstay-crown-street-bolton/There are also many in which the original notice was not received or discarded/ignored.
You will also see that the majority of cases in which DCB Legal acts on behalf of the parking company, properly defended claims are usually discontinued before the court fee has to be paid.
If you paid from 09:00 to 13:00 then you paid for 4 hours, £3.00 apparently, but you parked 08:45 to 13:05 and should have paid £3.20 for 6 hours. On such trivia do these large invoices (they're not
fines) get generated. A “grace period” of ten minutes is allowed when parking is paid for, but you appear to have exceeded this too.