I can't think how to word this email so it's assertive, not aggressive or apologetic. I've over-thought it, and can't get the right words together.
Background: I work part time hours - like 10.30-2.30. I've already been asked to come in an hour earlier earlier on one day a week, and stay an hour later on two days a week. I've done it because they've been understanding of my circumstances in the past, and if I need time off for DC appts, then the time is already made up (not that I've ever needed the equivalent of three hours a week!).
Now I've been asked to work later four days a week (so go in later) and I don't want to do it - it impacts on 'my' time too much; I'm already out on the school run in the morning and it doesn't make sense to go home for 30mins before leaving again for work. I'm hoping they can't insist!
Can anyone write me a firm but fair response that doesn't sounds selfish please?