A Such cases are not unknown, though fortunately not common. Heads' conditions of service say they are required to give governors the information they need to do their job. Your LEA should be willing to help you. I can confirm that what you are suffering is bad practice. Governors should be involved in drawing up school policies and should have their own copies of them. Governors decide how to arrange their representation in interviewing for teacher appointments. Nobody else. As for pay increases, you don't have to agree as long as you can show you have discussed the matter against the criteria. It is a bad situation when individual teachers come to governors with grievances. If it is not a matter for governors, staff really must be encouraged to use their own internal processes of redress, through their line manager, appropriate internal committee or in the last resort a formal grievance. If it is a matter for governors, they should use their representatives and have the courage to protest if their 'representative' is in the head's pocket. And of course elect someone else next time.
Q Is it laid down anywhere how many deputies a school should have? If not who decides?
A No. As far as I know, it isn't even laid down that a school should have any deputy headteacher. Since the introduction of local management, it is entirely up to governors to set their staffing structure according to what they can afford and what they think best serves the needs of the school. If decisions they have made on such matters are thought during an OFSTED inspection to detract from the quality of the work done by the school, however, it is open to inspectors to say so and recommend accordingly. Most schools have one or two deputies, large schools occasionally have three, and I have heard of schools with no post of that kind. It is, however, essential to have a head teacher! If there is no designated deputy, a senior member of staff will be named to stand in for the head as necessary.