They could have a major problem if the original owner of the account is running another business as the ebay figures will be included in their tax obligations, the only way round that could be for the original 'owner' could employ the OP to run the ebay account and pay them whatever the profit is going to be and the OP includes that as wages on their tax return, no idea if that would work.

only if they also paid Superannuation as well pj!