Lop sided front spring suspension

[jdd]

Greetings all, I’ve been a member here for a little while after purchasing a 2004 E53 diesel sport recently.
So far it’s been a great car however; recently I noticed that it has a lean towards the left side.
I’ve measured the ride height on each of the four corners and the problem seems to be originating from the front left which is about 30mm (a little over an inch) lower than the front right.
I understand this vehicle has airbag suspension in the rear and a conventional spring setup in the front.
I’ve done a search on this forum to see if this was a common problem, but 99% of the threads I found were in relation to airbag suspension and the remaining threads weren’t really all that helpful.
Has anybody experienced a similar problem or knows what the common cause(s) are of a saggy conventional spring front suspension on one side ?