As a workaround for now, I've uninstalled the Guix-managed toot and 
installed toot (0.45.0) with pip instead.  This seems to work.

-- 

Kind regards,

Dan Hatton

                 Dr. Daniel C. Hatton

E-mail:         dan.hatton@btinternet.com

SIP:            dan.hatton@sip.linphone.org
Signal:         dch.28
Telephone:      +44 (0)1223 832603