We will have a 2.8m ceiling and Westin have advised their Stratus ceiling extractor would work - in fact they don't set a height limit just say it should be set at the highest point in the room. Might work for you? We also have two skylights but our other one runs the other way so as to best allow light into the internal seating area (where your utility is) - so ours won't match at all! if you want symmetry though, why not push your other one over to the side as well- wouldmake lighting the dining table easier!

Could you use the "Solatube" system? Then the hole for the skylight would have a minimal effect on your ability to use your roof deck.

Can anyone help? We are building a 3m extension with floor to ceiling glass doors (2.5m high x 8m wide). I have been warned the room could overheart and we need an opening skylight , but they are expensive. The house is east facing - can anyone tell me if this is necessary please?

What do you mean sitting on the roof? Does it have an upstand? Is it on a tilt to let water run off. We have two glass skylights in our flat roof but they do not sit directly on the glass, the builders built an upstand about 25cm high and then the glass sits on top of that. And the glass is double glazed and in a frame to protect it. And it’s on a tilt. What you’re describing, if I’ve understood correctly, sounds like a bodge. A leaky bodge. Do you have a picture?