It was time fit the plastic runners to the companionway slide.
I covered the pieces of Starboard plastic (yes, that's really its brand name ...) with masking tape and marked up five screw holes in each strip. Like this.
Then I carefully drilled the holes on the pillar drill, as here.
I countersunk the holes with a cordless drill and drilled pilot holes in the slide.
It was then I realised that I had assumed that the plastic strips were the same length as the slide. They aren't - they are slightly oversize.
As a result the end screws in the runners are very close to the end of the slide. It doesn't matter but it's a bit annoying ...
This is what they look like when fitted.