We had air conditioning installed a few years ago. I had lots of companies to quote and went with All Seasons Air Conditioning Services Limited (Tel: 0208 502 4543) Really happy to recommend them. We wanted the unit itself on our main roof up next to our chimney and out of sight, which All Seasons were happy to do. A few other companies wanted to put it in our back garden or on the side return roof. All Seasons sent out a chap called Eddie who was by far the nicest and most knowledgable of all the people that came to quote. They come every year to service it and the guys that come are polite and punctual.