I had this built by Dan from the bike shed company 2 years ago and it cost £714 then. This links to their website and shows the type of bike shed (Pedalbase 3). Ours sits beneath our Kitchen window so it doesn't obstruct the view into the garden. I'll get some photos up here in the morning.
Let me know if you're interested at the £300 mark and that you're able to collect it from Wallingford, Oxfordshire.