play a straight bat [British]
to try to avoid answering difficult questions
But last Saturday her interviewee played a straight bat, referring all inquiries to his solicitors before driving off.
[old-fashioned] to do things in an honest and simple way because you have traditional ideas and values
Amit, then 14, was very surprised to find that playing a straight bat was not considered all that important in his new school.
Easy Learning Idioms Dictionary. Copyright © HarperCollins Publishers