I seriously love this idea for the downstairs loo. You could create a screw or catch at the end you can't see in the picture so it is easy to remove from the wall and put on a toilet roll. They do artificial birds at Rockett St George.
Victorian Toilet Roll Holder. A perfect reproduction of one first made by the Sanitary Paper Company in 1884. Shown in nickel, also in brass. http://www.priorsrec.co.uk/nickel-toilet-roll-holder/p-41-42-386