All sounds reasonable Col.
The 63amp switch is the isolator. It is not the load rating of the consumer unit nor is it a fuse size, it is the current the switch can safely disconnect.
I think if you look closer the breakers will have a rating and probably be type B. A lighting mcb will be labelled B6. This tells you it is a type B breaker rated at 6 amps, there will also be a voltage rating.
If you have lost track or need to know for whatever reason again look closer, the electrician should have labelled each circuit in the unit and on the test certificate.