https://www.nhs.uk/conditions/baby/health/colds-coughs-and-ear-infections-in-children/
I wouldn’t take him to the GP for a cough unless it had lasted for more than a couple of weeks with no sign of improving. Or if he had a fever with it and wasn’t himself.
Would only take her for a cough if she was wheezing/crackly chest
I took my LG with a cough as needed reassurance that it was just a cough and I wasn't missing anything. They saw her and did some checks and it was just viral but it put my mind at rest
I would take my LO to GP if her breathing was fast as well. And her chest is sucking in, even just a little. If he chest sounded rattly I'd probably take her two. Have been there several times with my December baby with a few chest infections. Trust your gut. Even if you can't put your finger on ità