Why you ask, ....
The paperwork states to use Merlin only so you should follow manufacturers guidelines to keep to regs, although we do have a few options because Schneider are Merlin Gerin and they also do Square D with the sprung 2pin plug in mcbs... these are molded to the same spec and are actually the same mcb but have a pin attachment added, remove the pins to get an identical mcb.
This will of course be generation of the mcb dependant but Merlin boards are good for been backwards compatable.
So to sum up -
Schneider, Merlin and Square D are the same molded breaker with different brand names ... although older gen' won't be the same or some of their obscure ranges.
They are all expensive and if this is your concern ...its tough, they are what they are.