Thanks guys
I gave Forge a bell this week and enquired about their revised piston for the 007p and without any provocation they offered to send one out free of charge which is damn good service IMO
It arrived next day so I thought I'd rebuild it while the kids were in the bath
What you get in the kit...

new piston (left) vs old (right)

You can see the added O ring for the seal on the newer piston rather than relying on the metal to metal seal of the old
All the parts cleaned up and ready for some new lube and O rings

and built back up

off to the bin with these bits

Definitely feels like it holds boost better but I knew the DV needed rebuilding anyways. The addition of the O ring on the piston is a definite improvement though and excellent value for money being free!