Did this not so long ago with the help of my Brother in law. We tied a
length of rope through the tap-holes, walked it to the top of the
stairs and manhandled it until it was lying upside down on the top few
stairs. After that it was a doddle for me to gradually lower it with
the rope while he just slowed it's progress down the stairs. Note
important point, if the rope snaps, make sure you are the one at the
top of the stairs.