Just to point out to anyone here not yet familiar with British systems that this should be 230/240V phase-to-neutral, 400/415V phase-to-phase.
What earthing arrangement is being used here? Assuming your supply neutral is earthed securely, the only way I can figure to get the voltage readings you state a half mile away is if it's TT earthing at the farm and there's a fair amount of underground metallic pipe between the two locations as well.
By the way, what's the newer meter feeding? Separate single-phase for the house maybe?
(Can't make it out from the pic, and that Marks & Spencer bag could be hiding something!
I guess we should at least give the guy credit for using the right phase colors on his jumpers!