Not sure how much luck you'll have here, as this forum (and Gradcafe generally) appears to be very heavily focused on American universities with a few Canadian schools as well. Hopefully someone has information for you. Serious question, if your interests are sociolinguistics and pragmatics, and the faculty at Oxford aren't doing that, why are you so hung up on it?
On the American side of the house, I have repeatedly been told (including by faculty who sit on AdComs) that the strength of your SOP is very important in terms of determining your fit for the department. Did your writing sample or C/V have anything indicating your interest in syntax and typology? Those are the only other ways, at least in my application experience, to demonstrate your interests outside of the SOP. I'm not trying to be discouraging; based on what you say here your credentials are better than mine and it looks like you've worked very hard.