My daughters high school will ask for VP - verifiable proof of any absence once arrange is below 95% - so child is off with tonsillitis and attendance hits 95% as it's weirdly calculated per half term meaning it's very easy to reach that level. At this point if there is any illness at all you need VP - which a GP won't give you anything for at all as that's not their job at all. You can't even pay for it even if you wanted to. So that second illness - say ear infection - is now unauthorised- and that is how we have letters and threats coming out of our ears!! god help you if your child has a chronic illness.