Not a long post here, just a little guidance for anyone frustrated by this small problem.
Anyone in the UK who has a BT Broadband package will have access (and themselves act as a point of access) to BT Wi-Fi – and FON, globally – hotspots.
Now, if you’re (some say unfortunate) a Windows Phone owner and use the BT Wi-Fi app, you’ll notice that the app makes BT Wi-Fi hotspots, annoyingly, take priority over your own full BT connection when at home. The trick with this is that you have to just delete the hotspot after you use it from within Settings | Wi-Fi | Advanced | (hold down on network name and press delete).
People with Apple devices can set auto-connect to off and to forget the network. Similar procedures will likely apply to Android and BlackBerry.
Though this is a tad annoying, the BT Wi-Fi app is good for automatically driving you through the login procedure at hotspots.