Thanks guys,

Some really helpful information here. Flex is blue/brown double insulated and so is the lamp-holder - to fit the lamp-holder to the existing bracket (which is part of the lamp-head tensioning mechanism) I've had to thread its neck (where the wires go in) and use the original threaded brass tube which holds it all together - the wires at this point have extra sheathing around them and the tube ends are chamfered and smooth - even though the risk here is minimal that bit of brass warrants having it earthed. Good to know.

Thanks again.

Wal.