Radicalsteve,
I wonder if you have tried your unit with single ended input? I tried this on my MkII, and loved the increased dynamics I got. Not going back unless I get another unit and run in balanced monoblock mode. As I understand it, the stereo amp converts balanced input back to SE, anyway. For whatever reason, I liked SE better than balanced.
FWIW, I really, really like my MkII. Best amp I have ever owned, including lots of tube gear. I have owed the same speakers for 18 years, and the Spectron is easily the best match for them.
Do you really like the remote sense cables and have you tried conventional cables?