You’re lucky to get tickets for the Sunday so late
Years previous it sold out in Spring
I imagine there is a bit of a cut back on people’s spending this year
Actually last year Saturday was the only day to sell out. This year, Saturday tickets sold out back in May and the other days are now showing as limited. Last weekend's FoS sold out for the first time in a while so I suspect the Revival will too.
Auster, a few ideas:
Goodwood's official ticket reseller is
Twickets, although there are not often Revival tickets there.
A more likely source is
Pistonheads. It's a fan based forum so profiteering is strongly frowned upon.
If you're not lucky, have you considered going on Friday? The track is still busy with a full schedule of practice/qualifying so whatever your particular interest you will see it in action. You can also take in all the impressive on-site "set dressing" at leisure letting you concentrate on the races on Sunday.
Visit "Over The Road". If they have the same system as the last two years, you can enter that on Saturday with your Sunday ticket. Plenty to keep you entertained and a big screen to watch the track action.
Good luck, hope to see you there.