I have tried several 'fixes' but cannot get thesaurus for uk english, any ideas?

The thesaurus is installed, and ticked in writing aids, and will work if I change all my settings in Languages to USA English. !!
Now I’m quite a fan of the USA in general and the ideals embodied over the pond, but not quite ready to surrender my heritage. So if anyone out there knows a (Tested) way for me to have the old country’s spelling and a thesaurus I would be very grateful.
Can do in Open office!! and even Microsoft managed it!. What gives with the truly global community of Linux?

It might be good if you explain in details what exactly you did.