Ford Fiesta - Ford Fiesta Mk3 Fuel Filler Rust - craneboy

I have a 1989 (G plate) 1.4 fiesta ghia. It is in exceptionally good condition for its year, both inside and out. However a small amount of bubbling has started to appear around the fuel filler area.

I have read else where on the net that this is eventually pretty much terminal for MK3 Fiestas. I would like to know if this is the case, and what sort of costs would be involved in repair. Despite the cars age I would be willing to spend a certain amount on it, as it is a reliable little runabout.

I have seen on ebay that replacement panels can be bought for this area. is this the best method of repairing the affected area?

Your advice is appreciated.

CB