look up ebay for mk2 golf repair panel
complete panels like wings etc will be a bad fit as not OE but for repair panels that are gonna be cut & welded in by an experiences welder things like the fuel filler repair panel aint a bad job
though if the outer panel is rusting you can bet the inner panel will prob be 10x worse
for doors, you can pickup good 2nd hand genuine doors for cheap money, especially 5door models