Having reached that sort of stage of the evening, have tracked down two people on LinkedIn by clicking through the links of lots of people with those names in the UK until I found them. One was instantly recognisable from the photo, the other I had to get t__m__i to verify given that my face recognition is terrible. One is in Oxford, or was in 2012 (they didn't go to Oxford). Due to the 1.2 links of separation thing they both are 3 links away by LinkedIn i.e. me, someone I am linked to, mystery person, them. In neither case is the person I am linked to an obvious connection to them, in one case our Benelex software distributor and in the other a colleague from a previous job. Not necessarily planning to do anything with this info.