This is quite a boring post but I work in live music (albeit a very different sector) and am puzzled by the economics of it. I'm struggling to understand how they will break even never mind raise money for charity.
Most charity concerts generate their revenue from broadcast sales and building a wider fundraising campaign around that so you aren't making money from the concert goers but the people watching at home. I can't see how this will get a very big fee for streaming/broadcast rights. All those artists will be doing the festival circuit and touring - there's nothing exclusive or exciting about the line-up - people can see them very easily. They will have to create specific merch - and who will be paying £30 for a tshirt for a one-off gig with a lot of random artists who have very different audiences?
Even assuming that they sell out every seat in the arena at around £100 a ticket, that's £1.25M. Even if artists work for free I simply cannot see the costs of putting on that concert at sub £1m - Wembley hire costs, security, insurance, venue staffing, technical and production costs, organisation, artist travel and expenses, publicity and marketing and other fees. It's a complex gig - every artist will need different lighting, logistics, sound set up which adds cost to prep and rehearsal time. Wembley will make a nice packet out of all those £10 pints and pre-concert meals and as a north Londoner I approve of that.
Of course, after Manchester Pride going bankrupt and the general murky arrangements of GLP I am completely unsurprised that the financial organisation may not be the most robust. It may be, who knows, maybe they'll get the BFI (taxpayers) to stump up £1M to make a concert film like they did with Kneecap.