Removing misty double glazed unit from aluminum frame

[Durwin]

I am a pretty competent DIYer and have worked with windows before but aluminium frames are new to me.

I want to remove the glass without having to break it if possible. I can see what looks like beading but how does it come out?

Will it want to come out perpendicular to the glass or along the front of the glass? Seems to be held on with some kind of mastic.

 

[masona]

Remove rubber beading from inside with a blunt tool, then push glass unit back a bit from the front then unclip the plastic angle beading on the front.