Ok, so I had my front right strut replaced and picked the car up today. Had a look at the busted strut and have the following observation.

In the first picture you can see three elements:
(A) Is a metal plate
(B) Is a metal ring
(C) Is a o-ring

The top of the strut is to the right in the picture.

In the second picture you can see the same three components, in addition to:
(D) A larger o-ring

Here is my theory. The metal plate slides into the base of the upper part of the strut. When the plate slipped out the rest of the internals followed, and I think this is what caused the leak in the first place.

I may be wrong, and wont be able to test since the strut is going back to Arnott.

 

It's good news that the car is back on the road. Enjoy !!!