Scooterotica

All sorted now...on to the next problem
Baz

They shouldn't be that hard assuming you are using some long nose pliers.

As for the little cut out, I always fitted the circlips so the gap in the cirlip was pretty much directly opposite the gap in the piston. I doubt it makes an actual difference but it always kept my mind at ease

Agree with Donnie, i fit them the same. They are not the easiest circlips to fit but are generally considered the best, as circlips with ends on have been known to wear against the gudgeon pin and the wire end to come off and into the barrell with disasterous results.
You need some good quality long nose pliers and strong fingers and thumbs.