Yes to both. The firewall bit can't be the culprit otherwise IE would have the same problem surely. The extensions are :
FireFTP
Download Manager Tweak
Tab Browser Preferences
Mozilla calendar
I'll get rid of them one by one to see if anything changes.
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No joy

All extensions removed, default theme, all options turned off/on for the most liberal settings. java etc enabled
Just to clarify. What I don't see is the hyperlink saying "Download attachment ..." for each attachment. In IE I do. I'm stumped and probably missing something obvious