Just had a look on the National Rail Enquiries website and there's four scheduled replacement bus departure times from Brighton station to Worthing between 5pm and 6pm on Saturday. Tho I guess each departure time could consist of multiple buses. Still don't sound like a lot, bearing in mind it's...
Well you say that 'If you're any further east than Shoreham the bus will be so much easier/less crowded'. And they might well be, on the way to the game. But on the way back from the game, everybody who came by replacement bus for the entire length of the disrupted section of the West Coast line...