Wall pressure mounted stairgate (Marston OX3)

I have one in the loft with all the parts. It is wall pressure mounted so it just goes between the wall and the newel post and you wind it out to fix it, probably best at the bottom of the stair instead of the top in case of determined individuals! Like this: https://www.amazon.co.uk/Drilling-Screws-Extension-Safety-Opening/dp/B0CFYG...