In uk.d-i-y, Christian McArdle wrote:

I would use an unswitched 13A socket indelibly marked "lighting only" fed
from an adjacent 3A FCU on the lighting circuit. It probably isn't quite
compliant with regs, but it'll be reasonably safe.

The main safety issue is that when the next occupier plugs the vacuum
cleaner or a fan heater into it and the lighting MCB blows before the fuse,
it will cause the lights to go out and granny might fall down the stairs in
the dark.

(Not our granny: she doesn't do stairs at all any more...)

Indeed, to make it less likely to pop the MCB under an inappropriate
load, you could do a lot worse than fit a 1A fuse into the FCU. The 1A
will indefinitely feed 300W or more of halogen lighting (no, fuses do
not blow at 1.0001 times their nominal rating ;-) but if some mumpty plugs
in the vac, hair dryer, or fan-heater into the clearly-marked Lighting
Only socket there's a sporting chance that the 1A cartridge fuse will pop
before the 6A lighting MCB. Only a sporting chance, mind, given that
cart-fuses and MCBs have rather different time-to-blow-on-overload
characteristics, and that the MCB will be supplying other lights too -
so might be feeding 5A to other loads on the same circuit which Mumpty
just plugged an electric chainsaw into... but a sporting chance nonetheless.

HTH - Stefek