Is there a way to use the GAP IID tool to diagnose a leak from the one of the air bags? I've recently sorted my suspension fault on the dash which was C1A13-64 by boring out the compressor silencer with a 6mm drill bit and now works fine but my front end keeps dropping every night and I've rebuilt the front valve block.

It can’t detect leaks as there are no pressure sensors on the airbags or valves. The problem is either a leak or faulty height sensor. Pull the suspension control fuse and see what happens overnight. 2012 TDV8 Vogue (L322)

Pulled the fuse mate and the front end still drops so definitely need to get the stuts off for inspection

If both sides at the front dropped with the fuse out then more than likley a leak at the valve block unless you are very unlucky to have both bags develop a leak at the same time. Set the car in off road height and spray some soapy water on the bags and block to trace it 2012 TDV8 Vogue (L322)