Double glazed front door problem

[jackpot]

Our double glazed front door is a pain in the bum.

Basically one of the small latches on the edge of the door is catching the door frame when opening.
To expain more when the handle is pulled down to open the door the latch does not pull into the door as much as it should therefore sticking and catching the frame when trying to open it.

The door seems to lean to one side, therefore needing to lift the door as your opening it. This levels the door and makes it much easier to open.

Does anyone have any clues whats causing this, and how to fix.

Thanks

 

[masona]

May need Toe & Heeling method, see here