It's a pity you didn't seek advice before appealing because it's easy and quick to get APCOA Heathrow PCNs cancelled at the first attempt with a correctly worded appeal. But don't despair, you can still beat this ticket without paying, no CCJ and no impact on your credit score. We will tell you how to do that but you must show us the relevant materials, which so far you have withheld. All correspondence please including only one of the PCNs if they are all identical. Don't forget to redact all personal information, vehicle number and reference numbers.
Also, stop calling them "fines". They are not fines. They are demands for payment by a private company with no authority to issue "fines" and no enforcement powers. If you send you me a letter demanding money, you are not in a position to "fine" me for not giving in to your demand.