Accounts filed at CH wouldn’t show key details around contracts, wages and sponsorship nor would they show transactions between players, sponsors or managers made with off shore companies.
Financial Returns can be as detailed or as concise as the company involved requires. Some make detailed submissions to Companies House, so that prospective clients can see they're a well run, trustworthy company.
Now if the PL has a specific accusation, let's say "City claim Gabriel Jesus was paid £100k pw, but we (the PL) have received "credible" accusations from the "Hateful Eight" clubs, that City were making additional payments into an offshore trust fund totalling £4.8m per annum, to which Jesus is a beneficiary", then great.
Let the PL make their SPECIFIC accusations known, & City will answer them. So far all we've heard is:
Premier League: "The Hateful Eight clubs who wrote a letter to us on Arsenal headed paper, demanding City be thrown out of the PL, think City have been up to something dodgy. Can you help us build a case against you please?
City: Go fuck yourself. We'll see you in the Supreme Court.
It's really that simple...