PIVOT! PIVOT! 
Glad the balcony was able to handle the weight; modern balconies might not.
Indeed.
The house owner was a Mechanical Engineering professor (in the British sense of the word, not the grade-inflated US sense), so he probably considered that.
In fact he did consider it, and when somebody mentioned it the response was “well, the piano weighs about 700 pounds. Would anybody think twice about having a party in that room with the balcony doors open, and four adults weighing 200 pounds each standing on the balcony at the same time? No, they wouldn’t!”
Of course a balcony that was only meant to look pretty and not to be used for anything might have been a different story.
A very interesting thread! I’m playing around with an expression map to drive the GPO5 custom organ console with mixed results so far. I’ll try adapting the suggestions here.
Adventures in piano moving 
I’ve had plenty. I spent most of the 70’s as a piano tuner/tech including a stint at $&$ in the Concert and Artists Department under Franz M. Knowing the proper moving techniques for various situations and more importantly, which movers were actually qualified was an important part of the trade.
BTW, here in the US, grade inflation doesn’t extend into mechanical engineering and most of the other “hard” disciplines. The same cannot be said for some other “soft” disciplines. My son is an ME with a graduate degree. One of his high school friends, the son of a British IBM executive on a five year assignment here in the US, went back to the UK for his university (Southampton, IIRC) studies in ME. Comparing notes, they found that their respective programs were almost identical. If you can’t do differential equations, you can’t be an ME, period, end of story. Most engineering failures are usually ultimately caused by bean counters and poor management. See Richard Feynman’s comments on the subject in the appendix of the Congressional study on the Challenger space shuttle disaster.
Chris
I was talking about academic job titles, not necessarily about course content. In the UK “professor”, only applies to the highest ranked members of a university. In the US it is more like the French professeur - anybody at any level who teaches.
Some UK universities have adopted the US meaning, but even so only about 10% of academics in the UK have “professor” in their job titles.
At the “old” UK universities the proportion is much less. For example at Cambridge only about 200 of the 8,000 academic staff have the formal title of professor.
Here in the US, those are referred to as “Full Professor”. Lesser titles are Associate Professor, Adjunct Professor, Lecturer, etc.
On a more musical note, the pianists in old time American brothels were traditionally referred to as “Professor”, often pronounced as “Perfesser”.
Chris