Thanks so much everybody for your answers. I know it will be tight, but its getting pretty tight back in blighty right now so I'm considering a sunnier option. The school is offering accommodation, tax free salary and some other perks i'm as yet unsure of. I wouldn't consider it without them.

Until I posted the question I didn't know that the cost of living in Qatar was so high! So thanks for the info and keep it coming if you can.