How do I take off UPVC front door?

Hi all,

We have a UPVC front door that has a jammed lower hook
lock preventing us opening the door. I think the handle mechanism is faulty and something has broken off and presumably fallen into the lower locking point. I think i need to take door off to start to solve problem.

Door has 3 capped hinges (top, middle and lower). I have prised off a small cap at end of hinge cover facing door handle which has revealed a hex type screw. I have inserted the right sized hex key but am not sure which way to turn it as I can't tell whether i'm tightening rather than loosening, either way doesn't seem to make much difference.

Also , is it better to unscrew the hinges from the door
(assuming I can uncover the screws) and lift door away from hinge mechanism or better to keep hinges screwed into door and find a way to lift door off the vertical hingle bolts?

Any advice would be most welcome, traipsing round the back garden to the back door is starting to get a bit of a drag!

thanks