A lot of that might be going above my head and I know banks/investors are happy to keep handing out money if a business is big enough and repayments are being made but it doesn't sound like they've been covering their repayments if £425m is due in a year?

Borrowing more money at a higher rate to pay off an existing debt doesn't sound like a sustainable business practice.

Also "there are additional "liabilities" of more than £500m - the vast majority of which are outstanding transfer fee payments."
How can any club be allowed to continue signing players if they're not actually paying the transfer fees in a timely fashion?