It will all be fine. I thought we’d had this discussion before, perhaps not.
If you look at the total number of students in the country, discount international students and those living at home, then discount those who have already gone home or will do so before or after the window, then discount those who will travel by road (in their own vehicle, lift sharing, being collected, or by coach), you are left with about half a million people. Asssuming they spread themselves out across the window, and across each day (not before midday, obviously), it is still well within the capacity of the network.
A handful of places might have pinch points - on stations as much as on trains - but it will be localised.