@Skub -You're very welcome Davy, here's a couple more things...(You'll know all this anyway, but maybe for other considering it)
Under really good cans you don't hear any colouration from the room acoustics, dogs barking outside, an open window bleeding noise from outside.e. it's a constant environment.
The Stereo soundstage is close and very often exaggerated, which can be a help rather than trying to pick out stereo placement, my cans do this, and I'm glad of it.
Effects can be very subtley used, as I tend to do with LVox.
If you need to alter the proximity effect from a track, or if you want to use a de reverb plugin like SPL deverb, or proximity EQ it's much easier to do under cans.
You can listen really loud, or really quiet
You don't wake the others with noise
You get into the groove
The only time I'd rather have speakers over cans is when a bunch of you (a band + Producer or mixing engineer + Producer )are discussing a song...
With my production, a small part of it lies in the fact that I can hear every sound under my cans, and position it EQ, verb and soundstage wise where I want.
the only thing I would say is that Open Back Cans give a much more 'real/flat' sound, not very bassy at all, I only use my closed backs for tracking and drumming...
Do what your ears tell you Davy...(Others might feel differently about it, this is just my approach)
Hope it helps.