Hi Slookie
Sitting here in my warm sunroom with a Stanley Oisinn burning away quietly in the corner. Large church window and glass double doors with a high ceiling.The Oisinn is fantastic and very economical and really warm. However the cost of the stove ( 400 Euro ) is nothing compared to the additional stuff such as flues,collars,clips.brackets,fitting etc etc.I would estimate to be safe, around 1,500 to 2,000 Euro installed.This included a tiled plinth and tiling around stove and a flue brought above roof eaves.
Hope this helps you.
Kenbo