The scanned photocopy I put up had to be heavily tweaked in Photoshop to make it legible because the original I have is so gray, so yes it was a misread. I have got the correct valves in the unit.
I have had a reply from James Grant the arm developer which pretty much agrees with the conclusion I reached.
"I’d put the bass difference down to one or a combination of recording quality, mastering, format and system differences. The best way to tweak extra bass is tail down, so lower the VTA.
I haven’t found this delivers much to be honest, so don’t expect too much. I developed my arms to deliver the best bottom end so also compare another record that you know delivers good low end bass to confirm the bottom end delivery is still there and not compromised by wear and tear of the cart or other problem."
I'm generally very happy with the sound quality from the arm / cart combination as I concluded above. But if anyone can loan me a set of 10:1 SUTs for trial I would be happy to see if that makes the difference.