Stay, or go?
You may have left it too late to move for September, so that will decide the matter for this year. What you pose is the classic dilemma for many teachers. You are settled and enjoying your work, but in a small school there is no room for career development. So, do you go or stay? Where do you want to be in five and 10 years' time? If you'd still be happy where you are, fair enough, but if you feel you would be frustrated, start looking now.