Thank you all for your kind comments. I just tried to put my hat on and found it was suddenly too small.
MichaelS: The model is in 1:00 scale and the dimensions are roughly 15x19x17(h) cm.
Sharonpaints: You can get the model direct from the publishers:
3D Models collection - Maquettes
Look under Theatres, Cribs and Dolls. There's also a nice diorama of Mozart at Versailles under History and Arts. I'll be sending you a rambling story in the form of a PM.