I worry about whether you are competent to to this.
- You don't know the difference between a fuse and an MCB (and this is not pointless pedantry - your terminology betokens a great lack of awareness).
- You are replacing a 16A device with a 32A device, the 16A one has a model number 161 QEB and the 32A one is a 321 QEB, and you don't understand why.
What is the circuit? What investigations have you done to verify that you can safely uprate it to 32A?
Are you planning to apply for Building Regulations approval?