This seems to apply to your account -
Information for charitable organisations
If you’re registered as an eBay charity seller, you’ll pay a final value fee at a special charity rate. Your fees will be deducted and the net proceeds from your sales will be sent directly to the bank account associated with your eBay account.
If you’d like to increase your fundraising potential, you can set up your charity to receive donations at checkout and through our eBay for Charity website.
Are you registered as a charity seller, as that seems to be necessary to have payments to bank, without involving paypal.
As you have been invoiced it would appear that as far as ebay are aware, you are just selling for a charity, ebay would invoice, you pay invoice and then they pay you, which is unnecessary and a long way round.