Hi!
I don't think you are ghiving you LO too much milk - personally I would keep him on full fat not semi-skimmed, as they need it for energy (even tho you say he is chunky).
My LO (almost 2) only has a milk at night now (9 oz+), but has it on cereals & puddings etc.
He may not need the morning bottle tho, so if you think he is a little 'chunky'
maybe drop that one!!