Phoenix I think, even before piloting, questionnaires should be seen and approved by somebody with some expertise in questionnaire design.
Like you, I have considerable experience of questionnaire design. We used to use the old computer adage, adapted, 'garbage in, garbage out' about questionnaires.
I never answer a questionnaire unless I am happy with the design, which was why I did not answer the Gransnet questionnaire.
Good Morning Tuesday 23rd April St Georges Day