Socks: Bresciani for Berg&Berg
Shoes: Carmina for Skoaktiebolaget
I have two pairs of shoes made by Cheaney on the 2003 last (one of which is on the previous page...no love for spectators here...pfff :p)...
Anyway, point is I bought the first pair - a black double-soled longwing derby (a couple of pages back too), in my normal size of 9.5UK. I got the wider fitting (G) as the last looked quite sleek. They fit. Then I ordered the Henley oxford spectator, same last, same size, and it was too tight across the vamp. I sized up to a 10G and they are great.
The thing is, I don't have a particularly high instep - my other oxfords all lace over my foot just fine. But last shapes are a funny thing. Just where that line of stitching goes across the join between facing and vamp, that particular last was too tight. I'd not noticed it on the derby because of course there's room for the whole vamp to move.
Anyway, I suppose the point of this is that different lasts fit differently (doh!), but that the real guide is how well a shoe with closed lacing fits you: once you know that, I guess you're good to go with a derby, monk of whatever. But not the other way around. And makers' sizes vary from last to last completely - last week I got the new Henley II, same design but on the 175 last, and even though it's the 9.5, it's a touch too big.
Lesson: try shit on. And when you find something that fits well and it's an oxford, get more!