You ideally want a manganese product that is manganese nitrate and manganese sulphate combined. These two work faster than manganese carbonate.
I can't remember what nutriphyte is, I dare say if it is cold and wet a couple of litres of foliar phosphate in the tank with the manganese would not hurt, either.
I used manganese sulphate on that block, with the nutriphyte which is a pyroglutamic gubbins and some phosphite. Other farm I used 1lt of mangagese nitrate + 3lt manganese sulphate.