FWIW (and i bow to DrC completely here)
i believe all the 80's fox's were Araya made - i've only done a little research but i couldn't find an Araya bike of early 90's with the 'UK' wishbone seat stays.
My courier's frame sticker says "made in japan" but it's not conclusive proof that it is not just the tubing (although that seems unlikely) as it also has a assembled in Taiwan sticker on the bike itself).
The seat stays seem to be the giver - and the rack / mudguard mounts - as these appear identical on 80's Araya's and (UK) Fox's.
The rear end of my courier is all but identical to these.
The lugged frames start to disappear in the late 80's Araya / fox ranges - mine is lugged at the seat tube but not at the headtube for instance.
Anyhow as for the OP it's a lovely bike and must be incredibly rare (even) in the southern hemisphere.
Have a look at MadB's thread (just sold) about the Big Foot he uncovered and returned to it's former glories - it's a little brother to what you have ....
http://www.retrobike.co.uk/forum/viewto ... sc&start=0
look forward to seeing her shine
And