Okay, here is one other official source of spellchecking. This one is used by Google itself for its chromium project.
https://chromium.googlesource.com/ch...s/heads/master
You can grab the en_GB.aff, and the en_GB.dic and there is even a delta (extra words file) called en_GB.dic_delta (extra words to add to the official dictionary).
I checked the sizes and the en_CA, en_US, and en_GB all have about 50,000 root words and all use pretty much the same .aff file with slight differences.
These word lists seem much better in root word size.
So if you get a chance please try out that en_GB set and see if it would be a better starting point than our older en_GB. It is also interesting to see look at the words in the .dic_delta file to see recent additions that are not in the main dictionary.
Please let me know what you think.
Thanks
Update: See google version of en_GB zipped up attached for ease of access