i think a lot of named schools already have this model with their overseas out posts (like Brighton, Dulwich, NCLS in places like Dubai and Singapore).
because this stuff fascinates me have done a bit of digging on how Brighton college to it.
They seem to have two income streams -
they earn money for providing guidance and advice to partner schools across the world (last made up accounts for this separate legal non charitable entity it appears revenue is £2.2m). These schools are owned by other companies like Cognita (NBH’s owners) who own the Brighton college Prep school in London and the school in Singapore.
Then Brighton college itself also earns about £4m income from the international schools (again from the last accounts).
So not a huge amount compared to their reserves ( but I guess it helps diversify income streams and enhances reputation for them in an increasingly competitive market.