I am currently having a 2 storey side extension built and have encountered a huge issue. The rear wall of the extension meets the upstairs window in the middle. The architect has drawn the window in the wrong position. The builders discovered this at first floor level. We are therefore having to move and resize the existing bathroom accordingly to prevent the whole build being taken down and rebuilt. Clearly, the architect has not fulfilled his job by designing the (£2500) plane correctly. On the other hand the builder has not used common sense and checked upwards before building. The argument being he's 'built off plan'. The cost of the rectification work falls to us as no party is admitting liability. The architect now admits the drawings are wrong but will not entertain any financial assistance or liability beyond this. What is our legal stand point? Can we pursuit the architect from damages/compensation as such? Any help would be gratefully received