I found out about this group's work in February and promptly downloaded it to complement the GSX package.
Personally, I'm enjoying the UK voice sets.
FYI: Two minor issues that I will be mentioning over on their site, is that two or three voice messages seem to be playing early. One is after pushback, The wing walker says 'disconnecting and have a good flight', well before he cheerfully waves twice and the GSX text comes up. If you release your parking brake early you get into trouble.
The second is 'unloading completed and clear of the hold'. It seems to play at strange times.
Otherwise, I think their package is a great add-on to GSX, for people who prefer different accents.
Aussie