They are quite hard to mask up. Which screws have been troubling you?
Don't make excuses, I had real screw problems with my butt yesterday. I was making, for me, a very brave attempt at fitting the diverter from the downpipe to my water butt without causing a major disaster to the house and its foundations, the old bodger had put two different size screws in the downpipe bracket, while causing as much damage to them as he could, and then plastered them in numerous coats of kevlar armoured paint
As an aside, the instructions actually said 'drill a 26mm hole', does a 26mm drill bit actually exist?