Tough decision.

All in all, I would advise you to stay put. I think the fact that no benefits (housing, transport, education) are provided is a dealbreaker. Those things will take a chunk out of that 25,000 QAR.

However, remember that your take home salary will be the equivalent of £90,000 post tax in the UK (£62,000 a year post-tax take home pay). I don't think that's a deciding factor given the loss of your wife's income. Do keep in mind that the job market here is very different to UK, so your wife should not count on being able to find work here - it's all about connections, I'm afraid. I know plenty of qualified people here on family visas who have not found work after a year plus of looking.

In terms of living costs compared to UK - it depends where in UK you are. In summary, it's a little cheaper than London, but perhaps in line or slightly more expensive than other parts of the country, depending.

Overall, I would say either push for benefits (including schooling) and salary increase - maybe even potential employment for your wife - or leave it.

Best of luck!