None of the materials were bought or stolen during the making of this item
The bottom of the pipes go through a another piece of ply near the bottom, and are obscured from view in the pic.
I made up a box, packed it with different diameter plumbing tube (110mm down to 1") and squirted expanding foam between them to fix them.Done the same at the back of the bench for files screwdrivers pliers etc
galvy dustbin does the job for me