\set Staff.timeSignatureFraction = 4/4

[Robert Blackstone]

Hi Martin,

Thank you very much. 
I managed to make a not-so-minimal working example by stripping my score of 
items useless for this work
And that worked.

I hope your code will work in my full score too.
In terms of working method I am quite headstrong and when I see all error 
messages on the console I sometimes have the impression that I am punished for 
that. 
Fortunately, things usually go well.

Thanks again. 

Best regards,

Robert Blackstone