Need replacement casement locking system (for Roto multi point lock)

I'm trying to replace a broken "Roto" brand multi point casement window lock system that came with a bevel that fit into an existing 4-1/2" mortise (see photo). In addition to the Roto logo, the number on the bevel is: WA032.

The current multi point locking track is just over 46". I need to purchase a white LH locking handle and all the parts that are required to install the replacement lock system.

Do you have any recommendations?

Thanks,
Robert