Hi I am looking for some advise on securing the undertray as it has dropped down. Several securing studs are badly corroded and won't hold a securing nut. Any information on how to replace the studs would be helpful. Thanks

The one in the pic doesn't look too bad. Try a wire brush on them and some oil then try running a die on the threads to clear out the rust, then see if the retaining nuts (are they plastic ones) screw on ok. 

Hi thanks for your reply. I'll try that with new nuts. The other ones were metal rusted through and split.

Put your VIN into here and it will give you parts applicable to your vehicle.

Use the Ford part number to perhaps find some off e bay https://www.catcar.info/ford/?lang=en

Or you may find nuts bolts clips etc from this universal supplier https://vehicleclips.co.uk/collections/all-manufacturers