Er, no, Deerey, I think you’ll find I said that Channel 4 is public money, which it is. Just because that money comes from (mainly) the private sector doesn’t make it a private enterprise. In the past Channel 4 was looking for a government bailout and I believe the possibility of taking money from the BBC licence was even discussed.
As to how Channel 4 is funded, its revenue does, indeed, come through advertising, which is why I said “they [Channel 4) don’t force you to pay to watch them”.