Letsby,
I think Sussex work that shift, or something similar. They may be able to tell you how good, or bad, it is. Out of interest where did you hear the 9 hour shift rumour? That would tie in with the other rumour circulating that the 20 hour coverage from the regional bases has been reduced to 20 hour coverage across the bases (24 hour units excepted). That's a pretty major change, that will seriously affect service across each region, for not very much saving in money!
I am given to understand that an email to the NPIA asking them to confirm or deny the rumour has so far met with a deafening silence. There seem to be a lot of press releases but not many answers.