Roger Mills wrote:

The current socket has 3 x 2.5mm T&E cables connected to it - which I
assume to be two for the ring main plus a spur. The cables all
disappear behind the cabinets (I didn't install them!) and there's no
easy way of knowing which is the spur - other than separating the 3
and finding out what doesn't then work, etc.

No multimeter?

--
Adam