One more thing for a Brit coming to Qatar to think about. If you are coming to live and work in an industrial environment such as Al Khor or Dukhan where i live, you pay nothing to live. No rent, utilities, Council Tax, water, income tax, petrol almost free, subsidised food and facilities, free high quality medical care etc etc. It came as a huge shock to us when we first came just how easy life becomes and how cheap. I would choose an industrial town over Doha any day of the week, no worries about rent hikes, paying electric bills for a/c to name a few.
Unless you have recently lived in the UK, it is difficult to imagine just how much of your money gets taken up by high cost, income tax, value added tax, stealth tax and so on. My main expense is buying British newspapers, I spend about 250QR per month!