The batten is about 1.5 cm - the screws 3 cm -well below an inch, if the timber is strong as you say, I'll just try shorter screws.
Thanks for the replies.
I'm trying to install curtain brackets onto a batten that's already up above the window however, the screws don't go straight through. Should I
a) drill a hole further into the wall for the screws to go in or
b) drill a larger hole to insert a wall plug or
c) get shorter screws (will it...