On 09/03/18 05:42, SteveE wrote:

I think I'll take this approach as it will be as easy as just taking a
single earth wire down.


You could legitimately take a single earth to the nearest light on the
same circuit that does have an earth. For this, it would be preferable
to use a single insulated earth wire with green/yellow insulation. Often
called "singles" and available from all good electrical wholesalers
(some like TLC should be able to sell a length rather than a reel).

I don't have the regs to hand so not 100% sure if a CPC (earth) in this
scenario *must* be insulated, but it shows the purpose clearly which is
worthwhile.