There are no trickle vents in the uPVC window in my bedroom. 2.5m wide
x about 1.2m high.
Consequently, on winter mornings, there is a lot of condensation on the
windows. This is due to water vapour exhaled during sleeping. It's
amazing how much there is -- I have to sponge the windows down and then
leave the casement open during the day.

I am thinking of fitting one or two white plastic trickle vents. I
presume it is just a matter of drilling a few small holes through the
frame?
Any suppliers on line or in the high street? Wickes have some trickle
vents but they are for wooden windows, as far as I can see.

Anyone done this? Is it a DIY job or best left to someone who installs
uPVC windows?

Thanks,
Bruce