has anyone repaired a heated rear window track?

Has anyone tried repairing the tracks on their defender heated rear window?
I've got a couple out and I've been looking at painting them back where they have blown. I still have one that works in the middle but given that I have two wet dogs or wet cycling stuff in it most of the time atm I'm thinking it might be an idea to sort it.

Done it loads of times on the old Mondeo estate ... conductive paint and a steady hand, you can trim it back with a scalpel blade, but it might be better to use masking tape, (as long as it doesn't lift more tracks ...

http://cpc.farnell.com/bare-conductive/epaint-pen10/electric-paint-pen-10ml/dp/MK00208?CMP=CPC-PLA

I came up with just replacing the window as I had so many broken "tracks" - the silver stuff (conductive paint) couldn't keep up
It was about £45 for a window.
But I replaced the seals and fixings too - much happier now.
Just poorer
Ah well.

I tried repairing mine and it failed. So going to buy a new window.