Here's the map which shows the St. Margret's and Great Barr site. This
would've been most useful on the day.
Basically the tour consisted of walking down Sutton's Drive (past
the Isolation Hospital obscured by the blue 'Create Portal' note), through the gap between
Holbrook and Great Barr Hall (both covered on the next
tour) and to the back of the main hospital horseshoe complex.
Here's the main areas we explored:
Outbuilding. And most of it is outside.
Isolation Hospital. And rather remote.
Boiler House. And interestingly boiling.
Hosital Complex. And in a horseshoe shape.
Infiltration. And not in a horseshoe shape.