I suspect BT have cottoned on that people are using their own WiFi with Fon service to avoid exceeding their data cap and have restricted the speed. For email and general browsing 0.5Mbs is quite sufficient.
As far as I am aware you can not tell what type of connection you are using. This would probably require giving out too much information about the Homehub you are connected to and possibly compromise the owners identity/security.
The BTWifi help line is 0800 022 33 22 but I suspect they will be of no help in this instance.
Thanks for the replies and for moving this post to the right home.
"For email and general browsing 0.5Mbs is quite sufficient.", err I find it isn't really, unless you are a snail or never use big attachments or data-heavy websites.
I guess I'm only just getting used to the luxury of high speed, it was a case of having to be sufficient until we were fibre enabled last December. 0.5Mbs was the maximum speed I could achieve!!