Mine says c625e, which is either Canadian or from Singapore, according to the xda-dev page. I'd go for Singapore, even though it's supposed to be "unlocked".
What the darn, HTC... This is absolutelely senseless, why not let me choose my phone language, since that's an "unlocked" phone with "no" regional stuff added to it. Well, I really wanted to try Cortana, give it a spin, but I guess we'll all have to wait until the UK version is released... Or they will change it until then, and we'll have to wait until it's finally released, which will be in a year...
BTW I can find the cortana settigns page, when I do a search with Bing, but it just says Cortana is not available for this region...