The noise could change with different pressure if the pads are just through. Can you use a torch to check the clearance through the spokes to determine if the pads have plenty of material or not much? Squealing or grinding can cause an ABS sensor to malfunction which would give rise to the ABS fault leading to the suspension ecu also showing a fault.

No its not the discs, there is still about 12mm, i only replaced them about12months ago.
My problems with ABS and suspension inactive have been ongoing for months now, just different errors keep showing up. It all started when i had the car serviced by a BMW specilist and he flushed the brake system. I read on another forum that air in the system can throw up all sorts of problems but surely the air , if there is air would have been displaced by now?just another thing to add to the headache. Is there a way to check if tnere is air in the system? Thanks for your input.

Air in the hydraulic system will persist until the brakes are bled. Whilst I've had air in the brakes in many cars over the years, I've never experienced noise of any description, only that the pedal feels spongy and the brakes have been ineffective or pulling to one side. However air in the ABS modulator may make a noise if ABS is invoked but would not expect any noise with normal braking.

Is the noise emanating from the brakes or from the ABS modulator? Flushing an ABS modulator when it hasn't been done for a long time can dislodge rubbish that then can cause valves to not seal. The cure is more flushing until all the rubbish has been expelled. You could try locking the brakes on a gravel road to trigger ABS to see if that achieves anything.