Facts
1) This gig is for charity. Led Zep will not be paid for it, neither will Mr Goldsmith.
2) eBay directly profit from tickets being sold on. If they had a responsible attitude towards these things, they would allow the tickets to be sold, but only if all proceeds go to charity. Everyone wins then.
3) If you so much as mention some words in an auction, it is automatically pulled. This is because eBay are terrified of law suits from the "big designer labels".
4) As this is a charity event, they know they won't be touched. They could sort this out, but choose not to and by their inaction, they profit.