This is all down to lack of communication, OP - mostly your lack of communication.
You posted this thread just after midday. That means you knew he was planning on staying for at least another six hours when, actually, that was less than convenient for you. You could have taken him to one side then and said ‘Sorry Steve, I should have made it clear sooner - we’re going to be really busy after lunch getting the kids ready for next week. Are you okay to get going after the pub?’
Similarly, when he’d said ‘Fry-up please’, all you had to do was say ‘Oh - what I was going to say was I’ve got cereal, toast etc.’ Instead you chose to cook it anyway and silently seethe about it, telling MN instead of him.
Phrases like ‘Surely it’s common sense!’ all too often have an unspoken precursor, such as ‘Well no, I didn’t actually ask what time he was planning on leaving or say I’d be busy in the afternoon, but…’ You’re trying to blame him for not somehow sensing your view of the etiquette around this, but are taking no blame of your own for expecting him to be psychic.
I’m not saying it’s entirely down to you. As a guest, I’d usually try to find some way to get an idea of your plans - as you can see, your unspoken rule of ‘out after breakfast’ is far from universal. For example, I might say ‘Have you got time for Sunday lunch before I go, or do you need to get on?’ That gives you a chance to say ‘Oh, that would be lovely, but we’re going to be really busy this afternoon’ or ‘You don’t have to rush straight off after lunch, do you?’, or something in between. But this thread suggests that because he hasn’t done that, you’re sure as hell not going to either - not when you can grind your teeth and bitch on MN about it.
You think he’s tight; you think he’s inconsiderate; you make sneery jokes about how he thinks he’s so well-mannered, yet he doesn’t automatically understand what YOU consider good manners. Why are you even friends?
I notice you haven’t been back in a while. Perhaps he’s still taking up all your time while you silently panic that you haven’t got time to iron the uniforms or put the school books in a bag. Or perhaps you didn’t get quite the chorus of ‘You’re so right, OP, single childless people have it sooooo easy, they can’t possibly understand how hard life is for us poor overstretched parents’ for which you were hoping.