Well I up'ed the mag to medium! (I usually only take two eyepieces with me outside... no idea why but it is habit now).
So through the 15mm Celestron Axiom...
It appeared more green tonight. Definitely a bright green-blue in colour. It still has a globe appearance, but the edges aren't quite as sharp as a real planet would be. There is a slight elongation (like a mandarin in shape!). Not really a lot of detail but the colour and brightness make it well worth the effort. I have a long focal length (f/10), so I would recommend med to high power for those of shorter focal length.
Let me know how you go!
Ps I also observed six "new" (for me) globular clusters ranging from mag 8.6 to 9.9 in Sag, Del and Oph, plus Comet Garradd for the first time - so quite a productive night for a week night in the 'burbs.