In reply to gimmergimmer:
Yes they are fake and they're crap. Daughter and Son in law bought a brand new house with one and it was nothing but trouble. They're basically a fibreglass box with brick "slips" stuck on with mastic and then pointed up. They're fixed to the roof trusses first, then tiled around afterwards. Once the pointing falls out, rain can get in behind the slips and runs down the box, under the flashing and tiles and unless the felting is up to a very good standard, which I doubt it will be, the rain gets into the house.
We had the roofers back to "repair" the chimney loads of times, even to the point of having another chimney fitted. Needless to say it leaked every time. The cost must have been enormous with all the scaffolding involved every time. In the end, we managed to get it through to the SIL that a dry house was better than having a plastic chimney on his house, and had it removed. Not many chimneys left on houses on the estate the Daughter lives on now. They've mostly been removed.
They're shit, avoid them at all costs if possible. New house Dormers are the same as well.