Check pipework, it might not be the rad.
It seems strange that one owner has had 7 rads and some are still on their first?
Maybe a bad batch from the supplier might explain it? Same scenario as the brakes?
When you make so few cars a year, small problems get amplified.
Agreed I had a multitude of very minor leaks from hoses after fitting new rad to my Classic. Eventually just one remained on bottom hose extension no matter how tight and what position hose clamp was in. Doubled up on clamps in that area and haven't lost a drop since.
Footnote: silicon hoses seem to be more susceptible to such leaks compared to rubber.
