Also shocked at this thread.
I employ people in my business, but not a nanny. I have had to sack a person before, but it is important to find out what is going on before sacking someone. If they have done something really heinous, then it is usual practice to suspend them while you investigate.
There is one thing I really don't understand: if your dh is off sick, then why did he have to go away for 3 days?
Did your nanny really have the opportunity to talk to you? If you are abroad 25% of the time, and work 80 hours a week from a place 100 miles away, when are you at home? I understand that it is important to have someone providing proper care for your children. But it does seem to me that in your circumstances, you do need more than one person. Also, in light of your work commitments and your dh's health, I really don't understand your decision to home educate, without employing a tutor. My own experience of running a business is that it takes over your life, and you simply don't have time for anything else. Whilst I understand your concern for your children's welfare, I do feel for your nanny, too.
And I do wonder if you are trying to cope with too much, Sindy, and maybe over-reacting because of your own stress levels? Is this post also a yell for help because you're drowning under everything you have to deal with? Other posters have suggested ways of getting extra support, especially for your SN child - please explore them. Even with a nanny, I would struggle to cope with running a business, 4 children, 1 of whom is SN, a sick husband, and a home being renovated around me.