On Thursday, June 14, 2012 6:37:42 PM UTC+1, The Medway Handyman wrote:
On 14/06/2012 17:30, Bert Coules wrote:

Scaffold tubes have 'feet' to protect the ground, may be you could
modify something like that?

Kee-Klamps, like scaffold tube fittings, but available in smaller tube sizes as well.
Drilling a paving slab will probably cause it to crack. ISTR that various roof edge-protection schemes on flat roofs had the tube fitting secured into a concrete block that rested on a paving slab.