Lighting clamps.

[Excalibur]

See piccy. Various assorted 32mm clamps, fit the Maplins type truss, ( and others. ) The ones on the top row will also fit 50mm tube, I think. £15 the lot, the big ones are around a fiver apiece on Ebay. The two long ones are Ultimax. Collection preferred, as the blighters are heavy. I don't know what carriage would be, but it's at your cost.

If anyone has any 25mm Ultimax clamps, I'm looking for a few. Thanks.