ac1951 wrote:

In my case I have, already in-place, a 2.5mm twin SWA cable connecting
my garage which converts to a 2.5mm T&E cable on the outside of my
house. This is connected to a 6A RCBO in the CU. (Total distance circa
40M)

In the garage is a 2 way CU with 2x5A mcb's, one feeding the lights
and the other feeding 2xDouble 13A sockets.
I use the sockets for basic power tools (drill, planer, sander etc)
and also electric lawn mower. All the tools are double insulated and
therefore do not have an earth.

Is this installation legal ?

I can't answer that, but to help those who can you will also need to say
what, if anything, is connected to the armour of your SWA. The actual
connection to the armour is in the form of the brass gland(s), but what
is connected onwards from here?

Pete