Few days ago I had a brain fart, when cleaning my ears with JOHNSON'S Baby Cotton Buds. I removed the lid to have a cotton bud and looked at the lid in my hand. It has 90mm diameter and fits neatly on the top of the strut bolt recess.
Attached to the bottom side of lid M14 nut by using construction or industrial adhesive. Found left over from some previous project, black rubber U-edge trim and 4 recesses around the lid rim gives almost a manufactured look.