The cutlass bearing arrived, and it fits nicely inside standard PVC pipe fittings from Bunnings (hardware store). I will see how this works, and then epoxy it in place later to make it permanent. Note on construction: The pipe fittings are glued with PVC glue (they had to be tapped into place with a hammer; very tight fit), the cutlass bearing will be epoxied in place, after first roughing-up the inner PVC pipe wall with a rasp and coarse sand paper, so the epoxy adheres well. This makes a complete unit that can be removed and replaced simply by unscrewing the 50mm pipe fitting from the end of the 50mm shaft tube (‘shaft log’). Too easy !