Does anyone have the Bugaboo Turtle Air Nuna car seat?

[localbunny]

I've been given one by a friend (know the full history, zero accidents) and I cannot for the life of me work out where the button is to loosen the shoulder straps?! I'm pressing around the triangle marked in the instructions but clearly missing something. She can't work it out either as hasn't used it in ages. Can anyone help? Pic of model included incase there have been different ones.

Take the cover off (just at the bottom if you want) and it should make the metal bit you press much more obvious. You can then see if it's actually moving properly or if it's jammed somehow. If it's jammed with rust, it might mean the seat has been exposed to damp which could compromise the safety. But sometimes they are just a bit stiff and start moving again once you have found it.