A single phase charger is commonly 32A or 16A, which would be the additional load added to the existing setup. I’m sure you and your friend have these or similar dotted around your farm/s (see pic). All that would be needed, is the Tytype 2 plug on one end of the cable swopped with a BS4343 commando plug.
Oh yes, we a few of those on the farm single phase. Plus we have 3 phase and apparently multiphase over on our adjoining farm! I am just happy when I plug something in. it works!