Update:
Being a bit low on cash I took @
ForceofWill up on his offer. He sent his 08 rear shock to me and it arrived yesterday! It's in much better condition than I imagined it would be. My broken shock is looking pretty horrendous compared his. Mine has visible rust, wear and flaking paint. British weather? I frequently ride in the rain.
I've recently bought a Honda CBR250R rear hugger for my ninjette. I think that will help preserve my new-to-me rear shock better than my last one.
I've never picked up a motorcycle rear shock before. It felt pretty heavy. Is the Ninjette 08+ stock shock quite a heavy shock compared to many other bikes with similar shocks? Would a typical Penske replacement shock be much lighter?
Anyway: plan is to get it fitted very soon so I can enjoy faster cornering again with what remains of the summer. At a later date I'm going to upgrade my front and rear suspension to something better now that I know what a difference it makes. I'll get them tuned up nicely for my weight too.
Thanks to everyone for your help and extra thanks to Tom for the hardware!