It is all over the Internet.

As a google news for "betfair charges" will confirm.

In essence it is a deliberately convoluted initiative which retrospectively slugs long term winners whatever necessary to garnish 20% (22.5% according to others) of winnings.

I'm amazed no one here has started a new thread about this, so suggest someone does. Unless everyone here is unaffected because they have given up all hope of ever becoming a winner.