Complex sentence: A teacher by profession, he retired as headteacher of Wester Hailes Education Centre in Edinburgh in August 2011 having also been (2008--09) seconded as Headteacher to Tynecastle High School.
Split into simpler sentences: A teacher by profession, he retired as headteacher of Wester Hailes Education Centre in Edinburgh in August 2011. He had also been seconded (2008-09) as Headteacher to Tynecastle High School.