Changing lamp plug for 5A round 3 pin socket in lighting circuit

[SimonH2]

2A Plug and socket is more than enough surely.

Yes, and that's what we had in the older room when I went to uni in the 80s. But even back then they weren't commonly stocked. There was a trade in 2nd years selling them on to freshers, and the local Woollies had them.
There's also a question of compliance having a 2A "general purpose" socket on a 6A circuit. With a 5A you could make the case that a 6A MCB offets similar protection (if not better) than a 5A fuse (that might have 15A wire fitted )

 

[EFLImpudence]

Too much worrying.

What about a 13A socket on a 30A fused circuit - in which someone has put 100A fuse wire.

 

[SimonH2]

Difference there is that a 13A plug has a fuse - otherwise our RFCs would not be possible.
Similarly, IIRC there are some light fittings/accessories that are only rated to 2A - but again, they are effectively protected from overload by the size of lamp that's available*.

* Although yes, there are ways of working around that with adapters - but you don't see many of those these days. As a teenager I used to work on a farm and we had a cow that needed an operation. It was a displaced stomach and needed two vets going in from two sides with the cow standing up - and they asked (in advance) for more light that the 60W bulb in the middle of the shippen. So I gathered up all the bayonet adapters and tail lamps I could get together - and noted the 2A limit when putting it all together. Then one of the vets complained that one of the lamps was burning his ear