So tonight (though things are in reality way more along than the last post... and I'm just doing some non-linear Tarantino style blogging) I decided to make a small change based on a page from this slice of literature...
Building Valve Amplifiers by Morgan Jones
On page eleventeen or whatever... there is a note about using a nice heavy bit of wire for the IEC Ground connection to avoid unwanted noise by offering a really nice path to ground for the chassis. I remembered how the wire I originally used was from a section of green/yellow wire I cut off the Power Transformer shield. The stranded core was actually kind of small, compared to what you get down a good 3 core mains cable.
So... I found a bit of mains flex I have lying around and just sliced out the earth wire. I compared the cores between this wire and the old ground wire and the new one is way bigger. I installed it, and hopefully even if it doesn't make an audible difference, it's still a good tip as well as good practice.