Roger Mills wrote:

Bob Minchin wrote:

they do look a bit like the third photo down on this page
http://wiki.diyfaq.org.uk/index.php?title=Fence

Yes, indeed. They look the same as the ones in the Wickes video cited by
alan_m. I haven't got a clue what the big hole is for, though!

In case the screw "wanders a bit" on its way through the panel I should
think.