Have a look at Strippers Paint Removers. They do different formulations for different sorts of paints. http://www.stripperspaintremovers.com/I_want_to_remove.htm#2
For masonary paint, after applying the stripper, it generally needs to be removed with a hot pressure washer.
I'd avoid...
I moved into a new house in September and noticed that one of the rooms had a strange smell which wouldn’t go away, despite keeping the windows open. I can’t really describe what the smell is like as I’ve never smelt anything like it before. I thought it might be the carpets, but it was still...