Nope, none of those are 348s. I have the Lowndes, Hallam, and Westbourne on 348 in UK9E, and IIRC they all measure about the same. I don't have any US sized 348s although I did try the Barney's Tetbury in US10D and 9.5D.
If you're collating data, here are some measurements from shoes I've previously owned but have now sold (most to people here). I no longer have them so I can't double check measurements, but this is what I put in the listings.
Malton - Barney's version, US10D, 12 1/2" x 4 3/8"
Clifford - Barney's version, US10D, 12 3/8" x 4 1/4"
Winchester - C&J for Shipton & Heneage, UK9, 12 1/8" x 4 1/4"
Coniston - BB Black Fleece version, US10D, 12 3/8" x 4 1/4"
PSA: The navy Severns are on sale on Paul Stuart's site now. They had brown suede and calf on sale too last time I was in the store. (I think the store price was sub-$400, but I can't remember exactly)