Cantona's Flying Dropkick
vidi vici veni
They are using longer trains already and running as frequently as they can.
That's about it. I dare say if they spent a few million on upgrading the signalling they might squeeze an extra train in, but it's difficult to justify this for a couple of dozen occasions a year, when most passengers would only be paying pennies towards the costs.
Using Platform 3 at Brighton was only possible for short trains. My understanding is that it doesn't work now that the frequency of trains on the Brighton to London main line (which Lewes to Brighton trains have to cross to reach platform 3) has been increased.
Platform 3 was used for the Gills game at 18:20(ish), going straight to Falmer then on to Lewes.