Bosch HBM43B150B Hinge snapped shut

I find these very fiddly so I was rather pleased with myself when I took the main door off to clean the oven and replaced it with no problem (or so I thought!).

I did put the locking levers into place but it seems that the right hand one had not engaged properly. So when my wife opened the door later there was an almighty bang and the hinge locked shut with the other one still open and her holding the thing in place.

After a bit of juggling I managed to get the door off but now I am unsure how to get the shut hinge open so that I can refit the door.

Logic tells me that when the oven is shut the hinge locks round something in the recess and so it ought to pull open with something like a screwdriver in the hole in the hinge but I’m unsure if there is a particular angle that will allow it to open.

Could someone please help me redeem myself and advise me whether I can get the hinge open myself and the best way of doing this?

Thanks in advance.