After my condensation / ventilation questions yesterday have decided to fit trickle vents.

Is this easy, do i just drill a row of holes and screw the vent on?

Is there any metal in the UPVC frame? And do they go on the bit that opens or above this?

Not got any windows with these fitted so nothing to have a look at to see where they go!

Ours dont have any at all but most of the rooms have wall vents set high up in the corner of the room.
Not sure how these work since we had the cavity walls done but dont have any condensation issues..
Does your house have vents?

None of our units have them.

If you have height above the opening window, you can drill through the frame above, most likely just uPVC as the don’t normally have an aluminium frame over the top (they do on the sides for hinges / locks to mount to).

When the bare frames arrived for our windows, they just had slots cut in the plastic. The vents were then screwed on by the fitter. Don’t think it is any more complicated that that – unless you have a warranty on the windows.

OP I did exactly as you say, a series of cross holes drilled and screw the vents on. Just be cautious to not hit any metal or glass parts…
(Which of course never happened to me)