What do you call chiefs of staff in England?

Chief of Staff. This title can be given to senior officers of various ranks serving under a Flag, Field or Air officer.

The senior officer of the Army is Chief of the General Staff,

Senior officer of the Royal Navy is First Sea Lord,

Senior officer of the RAF is Chief of the Air Staff.

Note: First Lord of the Admiralty is a former post held by a Government minister in Parliament, a political appointment. This duty has now been taken over by the Minister of Defence.