Structural Engineer required

We need to have 2 dormers built, and a ground floor rear extension. The property is a 3 bed chalet, with an existing dormer on one of the rear bedrooms, which will need to be removed so a larger dormer can be build for each of the 2 rear bedrooms. At the moment, the existing dormer is set back from the downstairs outside wall by about 1 meter, and the new dormers will be build off of the plate on the downstairs exterior wall.