This is getting to be a habit . .Are you SURE of that, Liz?? My recollection is that the Imperial War Museum is on the site of the Bethlehem Hospital. My further recollection is that its buildings are not old enough to be the original - although there might be some old parts squirrelled away somewhere.
I also seem to recall (from another newsgroup thread, so this could also be totally wrong) that at some point the hospital moved from north of the Thames to the South (for those who are even less familiar with London than I am, the Imperial War Museum is south of the Thames. Apart from its Cambridgeshire branch, which is at Duxford, just down the road from me).
G.