kerrymaid,
again i am just reitterating Augusts post..... the proper time to object to the development is during the planning process..... and within the first five weeks of that process.....
the only possible way you have of interrupting this persons work is to prove to the enforcement section of the council that they are building something they do not have permission for, or not complying to a condition of planning.....
while im not familar with kerry co co, most councils require a 1.8 - 2.0 meter high boundary be constructed to the rear of dwellings, so while the kitchen may face your kitchen right now, it may not in the future...plus ground floor windows are not considered to overlook adjoining properties, only first floor windows....
last thing on this though, you will not be able to get this dwelling removed if it has permission as is......