Creaking rear suspension, part of the joy of owning a Morgan. . .My solution as follows.
1 Check (or get your dealer to check that the shackle bolts are correctly tightened.
2 Jack up rear (to take load off spring)
3 Wipe the sides of the springs with a cloth and GT85 (to remove general crud)
4 Spray with Castrol Motorcycle Chain Wax - this gets in between the leaves and works a treat
5 Repeat as and when required, especially if you have been out in the wet.
6 Clean hands and adjourn to the pub.
Bud