Hi Andrew,
I would suspect the pump you are hearing on brake pedal depression is the ABS unit.Did you renew the pump? or someone else said it was renewed?
Remove the cover on the EAS unit, LH inner wheel arch. Check the compressor runs.
If runs OK I would suspect pump output is low, check this with a pressure gauge connected to the purple output. WARNING, deflate suspension with Autologic or similar before connection.
From an empty system, start engine, leave drivers door open, pump should run & charge system to approx 140psi & cut out in about 6 mins or less. Close all doors, vehicle should raise & pressure climb back to 140psi in approx another 6 minutes.
Regards
Steve