[a_c]

This is perfect. Hopefully I can find some seats in April. My son is going to love it :)

Edit: I wonder how to book a ticket, e.g. the 22nd April London to Winchester one?

[Symbiote]

https://www.steamdreams.co.uk/tours.php?tourid=72721

Found by searching the company name in the final column.

[timthorn]

Even if you can't get a seat on a mainline trip, there are plenty of lines operating at lower speed that you could just turn up to. Some of the bigger names include the Great Central Railway, Severn Valley Railway, Bluebell Line, North Yorkshire Moors Railway... But there are plenty more across the country. That's one of the positive legacies of the Beeching cuts.