If you have the time and a British passport, DESS is the best option for a British curriculum. You will need to contact the school to determine the application date (usually the first of the year). Even of those who apply on the first day of applications and have a British passport the majority do not get places, so you need to have at least two other options. I would recommend that Doha College as one and that you also visit Compass and Park House. Schools are generally very agreeable to visits, and I would encourage you to visit as many as possible in the autumn and decide for yourself.