Might depend on the firm but I don't think this is the case generally - you can use the grant for whatever you want and the grant is tied to the location of study only. If you have to attend classes in London and live slightly outside it then that's actually a further reason to require the money to pay for travel.As a follow up question - if they only have a London office and expect you to complete the SQE in London, would they mind if you didn't live in London? I know that the commute would obviously be something to deal with, but would they expect you to live in London in order to get the maintenance grant they offer? E.g. to use for commuting to London etc.
I appreciate you may not have an answer, and I would definitely ask the firm if it ever came to it. Thank you!
Many more senior lawyers don't even live in London, they move to a more quiet commuter town/somewhere on the outskirts of London with their family, but they still make a London salary!