Not sure if the 2 are related, but it happened the morning after.
Just before Christmas driving over the moors in the dark, out of nowhere ploughed into some standing water and set sail temporarily. Day after that I got the attached codes, car doesn’t lose height but I also can’t adjust height either. Get the amber warning light on every drive, if driving in rain I get the red one too which switches back to amber almost immediately so I’m presuming water is some sort of trigger.
Any ideas?

You got your air pump wet clearly says exhaust valve try pulling out the pump and giving it a service.

The exhaust tube has possibly got water or muck in it and it's stopping the system from releasing air. The exhaust goes via a silencer and then back to discharge inside the acoustic box that the compressor sits in. Taking off the cover and having a look to ensure the exhaust is free of crud wouldn't hurt as a start. Then check connections, etc..

C1A1364 Pressure Does Not Decrease When Venting Gallery

Exhaust valve stuck closed

Exhaust valve does not
hold minimum retention
pressure

Gallery pipe
blocked/damaged

Pressure sensor fault

Air suspension exhaust
silencer blocked/restricted

Air suspension exhaust
pipe blocked/damaged

Reservoir valve block pipes
incorrectly installed
(unions reversed)

C1A3601 Exhaust Valve Exhaust valve, general electrical failure

Exhaust valve
disconnected

Exhaust valve harness
wiring short circuit to
ground or high resistance

Exhaust valve failure

Air suspension control
module failure 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed