In case anybody else is interested I only now found out that it is possible to use Thunderbird with Hotmail via the extensions on [broken link removed]. Two caveats - (a) follow the installation instructions carefully and (b) I found that I had to change the Hotmail extension options from using Screen Ripper to WebDAV for my account before it would work (with Screen Ripper enabled it was failing when trying to parse the Hotmail "bounce" page contents).