I am facing the same repair on my own 1.2 8v, I cant tell you if it's the correct seal, I know as much as you, but I am interested to know how much the seal was and where purchased, please let me know.
I think there is an updated seal you can get which is more like a rubber sleeve rather than an O ring, If anyone has any knowledge on where to get and how much these are, Im all ears.
Ta