The below is more than efficient to cover your needs but again part P comes into play and would advise a on site check by a part P electrician to sign off the work.

Its covering your arse at the end of the day.

IanT599 wrote:

Cable run is approx 8-10metres.

I've thought of running a 10mm cable direct form the main consumer unit to the welder. Running through joists and clipped to them to the attached garage. Last 2m in conduit.
Got a 32A socket for it for the garage. Worst case is if the welder I get is 16A or smaller then change to socket as required.
Got a 40A type c rcbo for it for the main consumer unit. 10mm cable is rated as 63A clipped and 52A in conduit so more than sufficient.

Going to run a second 10mm cable direct clipped and through joist but no conduit to the garage consumer unit.
RCBO type b 50A on the main unit feeding the garage unit.

Got a 16A socket for the caravan to fit too now as arrived.