Spelling correction ONLY works for US not UK spelling style

I have, I believe, downlodad both the US an UK spelling packs, but never, in any version, have I EVER been able to spell check in UK spelling style. My default setting is US spelling - is that the problem? I do editing and people send me papers to edit in British style, sometimes. It would be a horrible task to change my default setting every time just to edit such a paper…help please.

You need to give your PC a hint that you now want to use British English.
Tools > Language > For all text > select British English,

I have done that, with NO positive results. For some reason it corrects and/or offers synonyms only for US English.