Cool, thanks Gav. so your saing thak it to where your mains lead is soldered to the emi filter
and Chris, are you saying to run extra earth mods from edge connectors as well as from the boards?
Or are you sugerting to repin it? Im was only going to tidy up a few things and run earth from boards as he doesnnt want to spend heaps on it.

Yeh.. wherever your mains earth comes in.. this should go to the earth distribution solder board in the cabinet base. Make sure this is all good and solid with less then 1 Ohm resistance to all parts of the machine and reference all  board ground to this