HuntyCat, I know what you are saying but it is slightly naive. Minimum wages are different everywhere; there is a reason for that - you can't just fasten on to the UK minimum wage and say anything else is exploitation.
Almost every housemaid I have come across here sends the vast majority of her income back to the Philippines or Sri Lanka or wherever it is. They don't need much of it here in the UAE; accommodation is provided; food and toiletries are supposed to be provided, as far as I can tell the Filipino network here looks after itself in terms of providing everything for less (unofficial "taxis", etc) - in any case, the government of the Philippines, for example, sets its own minimum wage for overseas domestic workers, and it is absolutely nowhere near the UK minimum.
I"m not justifying anything; yes there are people here who pay ridiculously badly (most such people are not British expats) but the thing is there are still girls falling over themselves to come here - and these are cousins, sisters, daughters of maids already here, it isn't people being ripped off by dodgy agencies. So the 'slave' owner (is it slavery if you are paying the applicable minimum wage? not everyone does, but many people pay more) is giving someone employment, who wants employment, and supporting several people back in Sri Lanka/Nepal/the Philippines/Ethiopia. Whereas the people who sit and wring their hands and say that this is appalling - may have a point, but generally aren't doing anything at all for those people, who do desperately need it.
YOu can't change things from the outside muttering in. You can't, either, expect that if you turn up somewhere you will instantly improve it. But things are getting better here and elsewhere in the ME, and I firmly believe that some of that is attributable to the quiet, persistent, influence/persuasion/etc of expats just doing what is in their power to do.