YABU.
I had been a homestay student in the UK several times when I was younger and wouldn't feel well in this. Actually, I got to such a house once and it was weird.
To be clear, I totally understand some room safety check might be necessary, preferably when I am there, or just a quick glance over from the door, sure, by all means.
However, there is a big difference between dirty&unhygienic and untidy¬ according to your liking. For example the bed doesn't need to be made, it is just your aesthetical preference or habit. If you decide to make it, it is either overstepping or acting as a room maid.
And yes, I really see it as invasion - bed is kind of personal, and thought you technically own it, it is my bed for the time being, so yes, please don't touch it.
Airing is kind of grey zone here, it might be necessary and hard to communicate, or it can be just another way to police the student, hard to say. And as for hoovering, once the weird lady mentioned earlier rearranged my stuff for unannounced hoovering, it really wasn't a favour, it was just weird.