1. Get second hand Wings/Rear Arches.
2. Bodge them with fibreglass/Bodyfiller and hope for the best.
3. Make some fibreglass wings (Alignment issues, not to mention ill need an intact set of wings as plugs. but doable)
4. Weld in arches from another car.
5. Cut the rust out, seal the bare metal and cover them with some fenders (Mk2 XR2/MK2 Golf Gti.)
6. Ask you lot where i can get new wings!?
Lets try 6 as id like her to be original.

I ain't dragged through the forum to see if anyone else has had this problem yet, damn search function steals my life!