Go for Doha College. The best choice in Qatar for the British Curriculum. Someone mentioned Parkhouse. Friends of mine had their daughter there in secondary. The academics are not very challenging. Upon return to Australia their top-grade-Parkhouse-school-student daughter had to repeat a year, because they were so much behind.
My children are both in ASD. We tried to enroll them in Doha College, but since we have no british passport they were last in the waiting list. It should be easier for you. If your children should get on the waiting list you can enroll them in Cedars Tutoring Center. It's a bridging school especially for those kids on waiting lists.