is there a way I can use ACP without connecting to FM for the focussing
Possibly. You can disable FocusMax in ACP Preferences, Auto-Focus tab. However, if you have filter focus offsets set up (Filterinfo.txt) then it will fail because ACP uses FocusMax (or PlaneWave PWI) as a pass-though to the focuser to change the focus from one filter to the next.