Finally!

Limit the correction to 300-500hz, midrange comp Off..
Yes set both to 0 as Audussey deals the phase, you shouldn´t touch them. Also make sure the subs power all time, not set to Auto!
I finally managed to use the app today! The Mrs went out with the kids, would you believe the minute I plugged in the mic, the neighbours upstairs started vacuuming, unbelievable timing
I had to run it twice as I got -12 on the subs the first time. I got -10 on the second go so that was ok.
The extra control is great, I turned off mid comp and set the freq control to 400hz. I still need to tweak the subs a bit to get them back to where they were before.
So far after a couple of hours of listening, it seems to have let the speakers play more openly, they sounded good before but a little restrained maybe, it could be placebo though, and I need to do some proper listening tomorrow with some 4k stuff etc.