Hi Carlz,
Like you, I'm the happy owner of an 80ED, which I use with a Skywatcher HEQ5 mount.
I recently did the Rowan belt mod on the mount - not only did it get rid of that terrible grinding noise when the mount slews, it significantly improved tracking performance as well. I highly recommend it.
It's easily done by anyone with a bit of mechanical knowledge, but does require some special tools - ie a gear puller.
I'm not sure where you're located, but you could buy the kit from the team at
Testar - or take your mount to them and they will install and calibrate it for you, which is what I did.
I hope that helps
Gary