Expenditure on official residences is a matter for the relevant Ministers' Departments.
The information requested is not held centrally and could be obtained only at disproportionate cost. For the cost of routine maintenance on the flat above 11 Downing street I refer the hon. Member to the answer I gave the hon. Member for Lewes (Norman Baker) on 10 March 2006, Official Report, column 1836-37W.