I would go for the UK. In fact there was an article on the Torus site I think that explained why you shouldn't run 240v over a US plug.
BTW, in my building, I was getting 248v (as shown on the Transporter info screen). Turns out that SP Services is not responsible, but the building manager. Took some time to explain what I was asking and why it was important, but finally got the condo committee to instruct the on-site manager to maintain power within spec.