It says it is 75 mm on the page (hover over the picture, IIRC). :-)
Yes George - the rest is guesswork. I did openly declare that it is based on looks. I have used generic rising butt hinges in the past - not those from Screwfix.
AND I typed the wrong numbers!! I meant at 180 deg. rise = 20mm, at 90 deg. rise = 10mm.
But deep down I was trying to explain how Sam could judge for herself if she is in a shop looking at such hinges. And that the rise is totally dependent on how open the door is.