Improve error message re #7484

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Other language improvements re #7484

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Make changes similar to those suggest by Keith Brown re #7484

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge remote-tracking branch 'origin/feature/7484_better_language'