How to remove a conservatory hatch door

[lasix]

I have a large conservatory and I need to access an area right above it.
The easiest thing to do would seem to just remove the hatch panel (if I simply open it it will still be in my way) but I can't figure how to do it.
It's a PVC conservatory roof and the hatch is also PVC. There is no visible hinge, screw or anything that I can work with. I have tried to open the panel and move it in all possible directions, push, pull, twist... nothing seems to work.
Any ideas?

 

[crank39]

Lift it right up past the vertical and it should seperate

 

[ronniecabers]

Yep as Crank39 says, up vertical and remove , its like to c channels interlocked into one another , yo wont see it until you remove it