Range rover l322 suspension not going up problems

Hi all
I have a range rover l322 2005 (not the face lift). The car looks slanted from passenger side for some reason not sure why and you can also here the suspension hissing even when you lock the car? Anyone no why?
Right for the serious problem
The car drops down to access mode and goes back to normal height but still looks slanted from the passenger side. When you press the air suspension to go up (highest mode) it goes up but then drops back to normal with the light flashing constantly? I've been advised to replace the front shocks and a air compressor. But they are damn expensive and it might not even be that ://

Can anyone help please?
Not sure what to do

Thanks

Wrong section

Ohh sorry not sure where it goes. Where do I move it and how do I move it mate?

Press forums ( top keft )introduce yourself section then as suggested once you have done that forums too left again range rover then post your problem

Ok thanks pal