We all know Fords have always been crap for corrosion, but no where near as bad as Rover and British Leyland.
That's a bit of a generalisation. You're dead right about British Leyland, of course, and the Rover 100 got it's legacy from them, but I used to own a 75. It was a petrol 2.0L V6 so didn't suffer from the dreaded K-series head gasket issue. It was 10 years old when I sold it and there wasn't a spot on it. It had other design and build quality issues but the bodyshell protection and paint finish on those models, certainly the earlier ones, was spot-on. There are also quite a few 10-year-old 25's around that are still looking good. My wife had one for a while and it was also spotless.
As for Fords, my Mk1.5 is 10 years old and still holding up well. As I said all these old cars were produced at a time when the manufacturers were taking body protection seriously.