Check the bolts which hold the door stay fitting to the door are tight.
If they're OK remove the bolt which holds the stay to the car body, put some grease in the hole then replace the bolt.
If this works temporarily but the noise comes back, renew the plastic bush (VX part no. 90462823, cost approx. 50P) which is fitted in the metal strap at the car body end.
spud, June 2009