The UK / US thing is admittedly very confusing. Our boots fit large, like most work boots do, but the lasts are made in USA and we are a Canadian company, so to say that they are UK sizes isn't exactly true. It was before my involvement with the company, but at some point our work boots were listed as UK in an effort to help people adjust for how large they are. In general our true industrial boots do feel larger than our casual offerings because of the lasts and structured (often steel) toe boxes. It's really just a matter of semantics. What's the difference between UK or a large fitting US last? Nobody calls Red Wing or Alden UK, but for most customers our boots fit the same. The real problem with this comparison is when people think they have to go another size down from an American boot brand because we're supposedly "UK". If i did that i wouldn't even be able to get my foot into the shoe.
I don't know if i'm just lucky or what, but the sizing has always been pretty straightforward for me. I measure about a 12 on the Brannock. I like my shoes to fit snug. I wear a 12 in Nike and most athletic shoes. I wear a 44 in Common Projects, W+H, and everything else on that sole. I wear an 11 in Red Wing, Clarks Desert Boots, Chucks and some Aldens i've tried on. I'm a spot on 11 in the 110 and would be fine with that size in pretty much any of our lasts. On the 2030 i prefer a 10.5 because my foot is narrow enough (not THAT narrow) to fill the last out and i actually like how it hugs my foot. I'm convinced that most people talking about how narrow the 2030 last is are actually more bothered by how shallow the toe box is. I can't think of another brand that offers such a pancaked last, with an unstructured toe and such heavy leather. It's a unique combination and it's probably not something you will have felt before when trying on a boot.
I wish the tracings were fool proof, but there is human error on the customer's side and ours. Many of the tracings we get are done so poorly they actually do more bad than good. Ideally we'd have a good tracing, as many comparisons to other brands as possible, your preference for how a boot should fit, etc. Even with all that information there is no substitution for trying on multiple sizes in person. The difference is literally millimetres between half sizes.