Why on earth did you pay one of them? They have no idea who the driver is and their Notice to Keeper (NtK) is not fully compliant with all the requirements of PoFA. Only the
unknown driver is liable and as long as the
known Keeper doesn't blab the
unknown drivers identity, there is nothing they can do about it.
Also, you state that there has been a material change to the terms and conditions of parking as they have "implemented" ANPR recently. Has the recent introduction of ANPR and any other changes in terms and conditions been notified prominently at the entrance and throughout the car park?
Section 3.4 of the PPSCoP requires UKCPM to:
3.4. Material changes – notices
Where there is any material change to any pre-existing terms and conditions that would not be immediately apparent to a driver entering controlled land that is or has been open for public parking, the parking operator must place additional (temporary) notices at the site entrance for a period of not less than 4 months from the date of the change making it clear that new terms and conditions/charges apply, such that regular visitors who might be familiar with the old terms do not inadvertently incur parking charges.
NOTE: Examples of material changes can include introduction of parking enforcement where none has previously applied, introduction of time-limited free parking, or reductions in the time limit within which free parking is available. Given the need to avoid confusion and clutter at entrances the test is whether the fact that a change has been made is clearly signalled to drivers on entering the land and the nature of the change is clearly displayed thereafter – it may also be necessary to install repeater notices depending on the scale of the premises.
So, before we go any further, have UKCPM complied with their own ATA rules?