On brfares some contactless fares are showing, Chelmsford to Liverpool St. £12.90 (current Super off peak Return £23.50 or a Duo weekends only £35.25)
2x £12.90 = £25.80, so effectively half-way between the current Super Off-Peak (£23.50) and Off-Peak Day Return (CDR, £28.10). Given that evening peak restrictions will be introduced, that sounds about right - though of course there will be winners and losers.
There will be many more losers than winners on the GTR and SWR expansions to East Grinstead and Dorking. For example, GTR have simply halved the £21.50 CDR from East Grinstead to London Terminals when determining the off-peak PAYG single. They have seemingly ignored the existence of Super Off-Peak Day Return fares (£16.20 on weekdays, £17 on weekends).
Moreover, the CDR is valid to arrive into London from 09:45, making the 09:06 the first valid departure - but the 09:06 will attract the peak PAYG fare. Similarly, those returning in the evening will pay the peak PAYG fare even though the CDR has no evening peak restrictions.
SWR have been rather underhanded with the rounding they've used on their PAYG fares on the Dorking route. They've rounded everything up to give a nice little 20p fare increase for a day trip - again, ignoring the existence of Evening Out and Sunday Out fares. Those currently using "Southern only" fares would also be worse off using PAYG as there is no equivalent.