squeaks loudly (variable according to water on road) then it could be the roll bar rubbers (annoying but not urgent)
I heard a loud squeaking from the front suspension, but often only after it rained. Almost certainly located to the anti-roll bar rubbers that holds the bar to the chassis.
To prove it, the rubber was flooded and silenced with WD40 as a temporary cure. The cause is the plastic roll bar protective covering which grips/slips/grips/slips on the roll bar rubber to make the noise.
I cleaned up the surfaces of the roll bar where the rubbers fit with a bit of coarse emery. This roughs up the plastic sleeving of the roll bar to give a better grip.
The torsion bar is bolted on to the crossmember with a metal bracket (item 3) that holds the split rubber bushes (item 2) in place. Remove bolt (item 5) - this can be tight to start (18mm) and with restricted space can take some while to undo unless you have a right angle power spanner. Then unclip bracket to release the rubber bushes which are split so they can be removed from the bar.
Initially I did one side at a time; jacked up and with a second bottle jack to push the suspension up to take the weight off the anti-roll bar. Not easy to get the clamping bolt started as there is little room in there to swing a spanner - but otherwise the job was straightforward. (but see below)
Initially I smothered the inside and outside of the new rubber in thick silicone grease.
Reassembly is the reverse and it is good practice to have the suspension in the operating position before tightening everything up.
All quiet after a 50mile trip however this didn't last very long - and the squeaking returned. :-(
Inspection of the parts list shows that later cars had the rubbers bonded onto the roll bar. So plan Z is to bond the rubbers to the bar with SIKAFLEX 291 POLYURETHANE ADHESIVE.
I bonded the rubbers to the roll bar on my wife's car and that worked well :-) The bushes are still silent at 8,500 miles so this seems to be a good solution. :-)
It is essential (as I found out the hard way) to have both front wheels off the ground and carefully ensure the flats on the roll bar engage the flats on the rubbers - THIS IS NOT EASY TO FEEL and you need to have the roll bar entirely free of every connection to be able to guide it in so the two sets of flats locate. Some patience may be needed and tighten the bolts, checking all the time.
Once you have cleaned and copper-greased the threads you should be able to remove/replace the bolts much easier with a right angled power socket spanner - mine happens to be electric though an air-powered tool would be more powerful.