OK folks am in north hampshire. 1970's box house. Looking to put a small single storey extension on the back of the garage to extend the kitchen out sideways. The house is link detached so basically there is a wasted space behind the garage. Total size would be about 3 x 4. Put doorway in to link to garage, take out whole side wall of existing kitchen. The third side is a party wall with neighbours existing extension. Then a window to go on the back wall. A new boiler would be needed and would need to be moved to opposite wall (by 3 m). Would probably go flat roof as that is what most of the neighbours have. Would need it fitted to a level ready to put kitchen in. Any ideas on what this might cost in this area? Also realistically how long should I allow for it to be done? Huge thanks.