As we are not involved with enforcement matters, we are unable to comment on whether you have or are likely to receive a parking fine. All sessions begin at the time of purchase, except where advance session booking is permitted. In general, we are unable to accept payment retrospectively, primarily for enforcement reasons, although some operators do allow 'Late payment'.
If you have returned to your vehicle and a parking fine was not affixed to the vehicle then it is possible that you would not have been penalised. However, some enforcement operators do still issue parking fines by post so further details relating to the issue of a parking fine should be discussed directly with the enforcement operator.