Rated 4 out of 5 stars

@Stewart

This add-on hasn't been maintained for several years.

The official one is now mine: "British English Dictionary (Marco Pinto)".

Please notice that Mozilla updated all Firefox spellers to WebExtensions, but they only work with Firefox 62+ due to a bug in Firefox 60ESR.

Thunderbird still uses Legacy Extensions, so you can download the version here in ATN.

This review is for a previous version of the add-on (1.19.1.1-typefix).