What I am attempting to establish is whether you are able to open attachments with Firefox from an alternate e-mail address. I was attempting to ascertain whether you are able to open attachments from the alternate e-mail address.
What version Firefox is installed? (If you don't know, at the top of the Firefox window, click the Firefox button. Click Help, click About Firefox.)
To eliminate mail2world as the problem, please send yourself an e-mail with an attachment to your london.com address. Can you open the attachment with Firefox at the london.com address?
If you are unable to open the attachment with Firefox at the london.com address, please try in Firefox Safe Mode. Do the following: At the top of the Firefox window, click the Firefox button, go over to the Help menu and select "Restart with Add-ons Disabled..." Firefox will start up with the Firefox Safe Mode dialog. When the Firefox Safe Mode window appears, press the button Start in Safe Mode.