Two well known academies are in Rawalpindi which i know about them, both are luckily at the same place, Rehman abad, NOA and KIPS. Both have the good reputation as i think.
One teacher who covers the CSS course, lives in Commercial Market but i have forgotten his name. I dont know him personally but my few relatives who had been studying at him. It was their thought as once shared with me that he was good teacher.....