I have one from the 80s Crock..it is a comfortable ride, partly due to the fork rake i assume.
Once stripped, i found the 531 frame almost as light as my new Bianchi.
The frame is 531, dont think the stays are, and the forks definately are'nt.
As Jimbo states, the frame is 'long', but the wierd thing is the wheelbase isnt that much different to my Bianchi. But i do feel stretched out on it...i've never measured it all out to compare, but it does look long.
Not my favourite bike based on looks, but it was brought as a winter hack...and mine was in considerably worse condition than that one.