Internal Folding Table problem

[Smarchers]

2014 T5 California Sand Beige. We have a problem with a tiny compression cap that holds the sliding silver forks apart that helps lock the internal table in place while driving. One of the caps has come off, and the table no longer locks away. The wee cap has a hexagonal fitting, but it looks as though 3 of the little grippy flaps have gone. Has anyone come across this problem, or can anyone suggest a solution? There's no thread or ridge on the sprung bar to attach something else to, and this cap goes back on but just falls back off straight away. As it's sprung, the slider falls inside the runner and prevents the table locking into the plastic retainer, further up the bottom of the table. Any help greatly appreciated.