Thank you for your replies. They haven't used the word penalty, my bad. It is a parking notice served. I had a look through my tenancy contract and there is nothing to say about any parking spaces allocated, but I do have an OPC parking permit for display. I will get in touch today with the management of the building for some advise.

Hi, I need some help please. I live in a block of flats with private parking, electric gates. When my husband came back home one morning our parking space was occupied and he parked in a different space without checking if the parking permit was displayed. As you can imagine I have received a penalty from OPC. I wrote to them on the 25/03/2015 asking to provide a copy of the contract and evidence that they are entitled to receive the sum claimed. I have received a threat letter yesterday that they will provide those documents to the County Court, as they will proceed further. Right now I am a bit scared that a CCJ will be issued in my name. Please can you help? Shall I pay the £100?