ES Parking and UKPC both operate in this area which is a private estate in the centre of Manchester. The roads do not appear to be covered by Manchester City Council orders so it is a bit of a "wild-west" with the parking companies there.
One local employer with lots of staff in the area sent out this message
Spinningfields Estate Management have recently brought in a new parking enforcement company (ES Parking Enforcement), who are now responsible for managing and taking action in the event of anyone stopping or parking illegally within the Spinningfields Estate.
Due to these changes, anyone stopping in an area that is not a designated pick-up/drop-off point within the estate could be issued with a £100 fine. This is to ensure all roads within the estate are kept clear at all times. For awareness, the map below shows all the designated pick-up/drop-off points close to Hardman Boulevard (marked with a red X).
From Google Street View around the area you can see the type of signs that ES Parking are using. They are called forbidding signs and make no offer of a contract. As such they cannot claim breach of a contract that is not offered in the first place. In addition, the key term are hidden in smaller text on the signs. See Denning's 'Red Hand rule'.