**UPDATE**
ok, so I started by whipping the back off the controller to see hhow easy it would be to extract the battery, as it turns out, really easy, 1 screw holding the battery to the case and 1 plug connector. The battery is labelled up as being for a Bebop 2 controller (I think this is mentioned on another thread somewhere) so I started trawling the internet and eventually I found this MCBAT00014 Battery for Parrot Bebop 2 Skycontroller 2 P2 / SkyController 2 HD Power Edition (I hope its ok to add a link) it took a couple days to arrive but slotted in with absolutely no hassles at all and once the controller was all screwed back together it switched on with no issues and I've been able to update the controller, the ANAFI and both my batteries, so if anyone else is having the same or similar issues I highly recommend having a look at that link for a new battery.
Lessons learned, The SC3 will not work, even with an external battery plugged in if the internal battery is dead.
Thanks for the help guys 
I'm glad to be able to be flying again and I'll hopefully have some footage to post soon.
Whulf
