I've read the first three pages of this thread. You could refer to him as "him" or "her" or by their name. Do you refer to people as "immigrants" when you do your rotas?
Naturally it is up to the site moderator, but I would suggest that given the contempt with you refer to this person, your posts where you say "the immigrant" are nothing short of a racially discriminative statement - and could get the owner of this website into trouble as well as you.
On reading your first page, I had sympathy for you (I have a lot of sympathy and respect for the entrepreneur) - but that had faded by the second page.
Whatever opinion you may have for foreigners or blacks/asians, I strongly advise you to keep these to the pub and your very close friends, and to bring NOT ONE HINT of this into the workplace or your professional life.
Don't delude yourself - on my reading of this, you will be found (by the court) to have not followed the dispute resolution regulations to the letter (ERA section 90-something, as amended), the dismissal will be automatically unfair, this together with any race discrimination claim (which deserves to succeed, given your attitude) will mean you have to write a five figure sum on a cheque.
EDIT - just read the whole thread, and I am disappointed that not one of the other forum members felt that your racial contempt towards this person warranted a mention. I realise that most of us are probably white english, but business owners such as happyeater are happy to employ foreign workers (doubtless on minimum wage) and should really be able to see past the ends of their own noses.