The car has developed an intermittent whistling / tweet noise coming from front offside
After a few mins the suspension fault warning light appears
The car rises and falls correctly and without time delay
Any ideas as my local Indy doesn't know or how to investigate

Apparently as the warning light is on it can't be a squeak relating to bushes?
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2011 Autobiography, Fuji white, Le Mans interior
2006 HSE Black / beige 3 years from new
1986 RR Classic - metallic blue / grey - fantastic car

Does the compressor continuously run? 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Get your indy to read the codes as there is a light on there will be a code

How do I check re the compressor?
I understand it is not designed to run continuously as it will burn out

In the middle of France my indie although having built a jag rover to compete in the Dakar rally doesn't t have diagnostic tool! --------------------------------
2011 Autobiography, Fuji white, Le Mans interior
2006 HSE Black / beige 3 years from new
1986 RR Classic - metallic blue / grey - fantastic car

Front off side is where the front air suspension valve block is located. That'd be the first place to look if you can't do a code read. Check for leaks from the valve block and from the pipes connecting to it.

The valve block has three valves in it - one for each side (corner valve) and one that connects the two sides when required to allow for axle articulation (cross over valve).

Does the vehicle lower over night at all? A leaky corner valve or pipe would cause that, a leaky cross over valve wouldn't (as it would just allow air to move between the two non-leaking sides). A leak in a corner valve or pipe would cause the compressor to run pretty much constantly as well as cause the suspension to drop overnight.

If your garage doesn't have a diagnostic tool of some form then they shouldn't be touching one of these vehicles, to be honest. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Update and thank you to all who helped!

It was a leak in the front balloon so we replaced the strut.
All good no more whistles ......

Apparently if an error light illuminates it is never anything to with bushes etc ,

Cheers --------------------------------
2011 Autobiography, Fuji white, Le Mans interior
2006 HSE Black / beige 3 years from new
1986 RR Classic - metallic blue / grey - fantastic car