To report back: I am now going to Frau Müller at http://www.physiobaar.ch/
, in Baar Lindenpark. She seems very nice. Also she is kindly speaking patient High German with me (she may well also speak English, I didn't ask).
The other physios that people suggested were all too busy to take new clients, including the Kantonspital, who suggested Frau Müller.
(Well, they say "too busy" as they had no appointments in the next few weeks... that would be normal healthcare in the UK!)