Housing in Qatar is expensive.It varies with the area.For a decent 2bhk Fully furnished,you may need to pay 8k+ and for 3Bhk+,the ranges starts from 9k+.
In west bay side,where most of the offices,then it would be 11k+,so remaining would be your saving and living.

26K in government sector is a medium scale for an UK national..
All the Best.