Eyelets on wing upper surface
 

There's me being all know to my boss, and then he points out of the window...

...so, yellow painted eyelets. There were two pairs on the wing. Didn't look big enough to be hoist points.

(Real sorry, could have been 737 or small Airbus - wasn't paying attention)

If they aren't for hoisting, what are they for?

There's a rope that comes out of the ceiling next to the door over the wing. The end of the rope has a clip on it that attaches to the yellow ring on the wing, and it's to help people climb out and walk along the wing when ditching, etc.

If it's a 737, at least one State has allowed the ropes to be removed. The eyelets also permit ground engineers to attach a harness to comply with workplace safety practices when working on the wing upper surface.

missile hard-points for military derivatives ?

:) :) :) :)

They are also for attaching a line from the life raft.

I hope not. What happens when the aircraft sinks?

For A320 Series, to attach slide to when it has failed to inflate ie is being used as a 'rag slide'.

Cheers,
mcdhu