I'd be grateful for advice as to where I might get hold of a cast iron 10kg weight.
Either a "trader's" type, roughly cuboid with a long horizontal handle, or a "lab" type, roughly cylindrical, tapering, with a knob on top, would be fine.
Great accuracy of mass is not important. Second hand and slightly damaged would be fine too.
I don't want one of the types that people use for weight-training though - i.e. not the flat disc with a hole, and not the hand dumbbell type either.
Many thanks in advance!
Chris