Alright so your sticking with english adv and maths ext1.
Dont drop physics cauz you will probs do well considering your good at maths.
Unless you really really like jap, then dont keep it cauz you have primarily sciencey subjects so stuff you learn in one subject may crop up in another so...
well i guess it depends on what you wana do when you get out of school. i do ancient and its a lot of work but from what ive heard, so is legal. if you dont know what you wana do when you leave school, then choose the one you like more, or do the best in (Y)