And now the most interesting (partial) finding, which really
struck me. In one of the books I looked at in Prague there
was a reference on Kelley's house in Prague to Moryson's
_Itinerarium_ (1617). I had no time to check the Czech edition
of the part on Bohemia (and hopefully there are enlightening
footnotes there) but on coming back I had a look at the English
edition in the library here - and next to the piece on Kelley's
house, I find this:
In Old Prage towards the South, and upon the East
side of Molda, there is an old Pallace, where they
shew a trap-doore, by which the Queene was wont to slide
downe into a Bath, where shee used to satisfie her
unlawful lust.