Having played with the lamps a bit today - there appears to be a small issue with the plugin's interaction with LIFX-HTTP.
For example, if I set a lamp brightness to 50%, the lamp gets set correctly to 50% but LIFX-HTTP returns a lower value (say 35%) which my plugin then shows as the dimming value as it believes what LIFX-HTTP is telling it. When the next polling occurs the value is (normally) corrected.
So I am not sure what to do about this at the moment - it isn't a show-stopper and I tempted to let the dust settle on the V2.0 change before spending too much time sorting it out (even if that is possible?). In fact that's what I will do unless I get any feedback that suggests it is a major problem