Rated 5 out of 5 stars

has stopped working maybe with update to Firefox v19 have tried uninstalling and installing again.

Thanks for the reply Alrond and I would be happy to install 2.2.1 but have not located it yet :-)

I'm going to have to check when I get home from work later but WorldIP is working on my work PC also Firefox v19

This review is for a previous version of the add-on (2.2.0.1-signed.1-signed). 

Please install V2.2.1
You can download it from here:
https://addons.mozilla.org/en/firefox/addon/worldip-flag-and-datacenter-pi/versions/