Perhaps you could have a look at the "Headers" of your latest email from "Claire" because it'll contain some IP addresses which can be looked up for a physical location here : http://tejji.com/ip/ip-to-location.aspx?ip=46.228.38.200
EDIT2: If you're able to post here a REDACTED copy of the email header I'm sure there's some Network Techy type people who could look into this a bit further