I assume none of the towbar companies in the phone book will knock up a towbar? Othersire try Liam (posts on this foum and might have a secondhand one).
The bubbling above the rear wing is common. Water gets trapped in the joint between the bolt on lower section and the body and causes rust. If the body has rusted through then welding is the answer, but it's a tricky area to weld neatly as the panel distorts. It's not really a structural area so a cosmetic repair (filler and paint) is also common in that area.
