@Annette76
I am a live-in host, so that's not a problem for me per se, but I do sometimes need to ask a guest if I can go into their room to sort something or the other out and they never have an issue with it, but I guess that's a different situation.
I used to rent to long-term lodgers, and there was always a clause in the contract that stated that I could enter their room (with prior notice) for repairs or without any notice for something that was urgent. This is actually pretty standard in such contracts here in the UK, although I believe 48 hours notice for non-urgent repairs is the norm.
So, I don't think there is any issue with adding something similar to your house rules. However, if it really does make your guests uncomfortable, then you might have to think about limiting visits for non-urgent repairs and do them in between bookings.