Thanks to everyone for your valued input on this. I've decided to get a GSO mirror - they sell on Astronz for NZ$375 for a 10" f/5, I just can't really go wrong with that price
and then I won't be without a mirror either (Imagine if Eta Carinae went bang while I was waiting for my mirror to be recoated...
)
I've also just installed a new 70mm secondary from Bintel so that's taken care of too. I believe the Bintel mirrors are GSO as well?
It will be great to once again have nice shiny optics throughout, should have done this years ago...
I'll let you know how it goes with the new mirror once I get my hands on it.