So I have this fault and a google seems to suggest it’s a big issue on discos - there is a multi connector in the nsf arch and the wire to the sensor corrodes..

Is there such a connector on the l322 in a Similar place or does anyone have any suggestions what to do to fix?

https://www.disco3.co.uk/forum/solved-faul...ight=C1A09 Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Anyone 😂 Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Rather than guessing, what are your symptoms & DTC's, what does the 4x4i screen show? you can't really use a diagnosis of a DTC from a vehicle with a different implementation of a similar system.

If I read the eas module it’s showing pressure on all corners all is above board but for some reason I can’t see reservoir pressure not sure if that’s the iid tool limitation or the fault Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Right - I have (I think) identified the problem - the reservoir pressure sensor that’s in the Wheel well was soaking wet inside the plug . Disconnecting it makes no difference to the fault codes so I have ordered a replacement over expensive sensor.

The question is with the EAS not running how do I change it? I assume I can’t just unbolt it or it will fly out like a bullet? How can I depressurise the tank with inactive eas? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Before you change the switch, check the harness connector for corrosion, you might need new pigtails for the connector housing. I'd also recommend finding out how and where from the water got in to prevent reoccurrence.

With the system off, you can crack off the pipe fitting and allow the compressed air to vent slowly - don't forget to nip it back up before you run the system up though. On SDD & Autologic, there is a routine to deflate & depressurise the EAS which works even with DTC's set, it might be on IID - I don't use it so can't give you any hints as where to look.

The connector that plugs into the sensor? That clean and I sprayed with contact cleaner and dried.

I’m hoping I can plug the new sensor in without fitting and I will at least get no faults or different faults or it will run a bit at which point I’ll be happy to depressurise and fit Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

With the best will in the world, you can't check the condition of the connector electrical contacts without removing them from the housing, are the pins in the sensor corroded or discoloured at all? if so, then so will be the contacts in the connector housing - even if not, you should be checking them as a matter of course, if there is any corrosion at all, it will spread to the new sensor.

Be careful using the new sensor as a 'dummy', it will of course read zero pressure so the depressurise routine will assume the receiver is empty and may not open the valve to allow the air out...

No corrosion on any of the pins and I soaked the whole plug in contact cleaner so hopefully that should do the job.

I was more thinking if it started blowing it up for a few seconds that’s enough of a confirmation that I need to change it Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Contact cleaner isn't what you (probably) think it is - it removes grease and oils, that's it. It doesn't remove corrosion or check pin grip, or replace contact plating.
Still, if you're happy with the diagnosis and remedy, then I'm sure it'll be fine.