Home DIY

With the locking mechanism being two shootbolt rods and a central gearbox, are both rods moving far enough to fully engage in the keeps?
There doesn't look to be any wear marks at all on the keeps. So I suspect maybe not.

Is moving the handle actually moving the mechanism? If not, maybe the spindle has come loose within the handle and your not getting full rotation driving the gearbox.

Gearboxes sometimes fail because there's small idler gears inside, to change the direction of the two rods. Or the rods were just badly assembled in the first place.

With the window open, lock the mechanism. Check if the mushroom cam is actually going to go into the keep... or just touch the top of it.

If the rods are moving fully and tightening the cam has worked. Leave it alone

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Unless there's a gap in either of the two hinged corners. Replacement hinges would be unlikely to help with a gap on the handle side.
Likewise tightening the locking mechanism won't do much to improve knackered hinges.