(I might also say its not a 'business' she is running and in the manner it seemingly is referred to here IMO, more a 'service' like dog walking or personal training - your not actually selling anything and its payment for a subjective perceived value.)
Absolute Piffle, so a service isn't a business, an Architect working from home (or any other professional "service") isn't a business?
HMRC state that anyone grossing more than £1,000 per annum for any services provided is classed as a business, e.g. dogwalker, personal trainer, prossie, AND needs to register as a business.
I would also say to the SP, perhaps a respectful, potential client (new one) can not afford £350.00 to see you for 1 hour and perhaps some consideration should be given to them from time to time, rather than simply 'aligning with your goals' or however you put it.
Such regular punters I imagine did help 'build' your business as you call it.
Seriously, she isn't a charity or some kind of community service.
If she has regular punters that PREVIOUSLY paid for her services at a previously lower price and did "help" to build her business, then that would be something I'm sure she has considered.
But I see no value in her offering reduced prices for some random new punter, who most likely won't return anyway.