Yes, I'm a big non-fan of positive discrimination, the important word is discrimination, it doesn't matter what prosthetics you tag onto it.
Having seen adverts for 'Black Women only Social Clubs', or 'Free computer graphics training for Asians aged 16-21 only', while I understand that in some cases people that have just emigrated here require support etc to settle in, I don't see this as being any worse than had I seen an ad for 'White men only social club', which would have been assured a closing under the equal ops act.
Aptitude tests are commonplace in the UK, I don't really consider them discriminatory as such, mostly they consist of extremely basic, easy questions, and maybe the odd one or two related to the kind of job you are doing. I've personally never found them challenging, and if you're going for a job in finance and can't even answer 'What's 60 divided by 3', then the company really ought to know about it, after all it's their money they are spending.