It brings to mind the immortal phrase in the handbook "FIAT has solved the problem of corrosion arising from various sources..."
It does tend to make you wonder which part of the structure is about to dissolve next. If you listen carefully, on a cold damp night, you can probably hear a fizzing sound...
White Unos always seem to be worst too - the best Uno colour for resisting rust seems to be the mould-green Uno 45, followed by the French blue Uno 45... but I suppose I don't have much scientific basis for that