They are true to British sizing. The quick conversion is to minus one, though there is probably a cordwainer who could point out subtleties. The British system has a size zero and that throws us off. I take a size 11 here so need a British 10. They also have 1/2 size spacer that fits under the insole for a little fine tuning in that direction if needed.
That's good to know. Much obliged.