I seem to remember being told that it is actually invalid to alight earlier than the station stop on your ticket. Is this true? Does this not apply if there are changes involved? For example, Thirsk to Northampton is cheaper than Thirsk to Milton Keynes, yet one of the changes for Northampton is Milton Keynes Central if going via Not London. I'm assuming therefore it's perfectly allowed for me to buy a Thirsk to Northampton via not London ticket to go to Milton Keynes.
Also, at peak times it often saves money to extend the ticket to get a more lenient restriction code - For example York to Northampton is not valid before 0930, Thirsk to Northampton SVR via not London is unrestricted. What would happen imagining there were ticket checks walking into York station if I walked in with one of the latter tickets , or if I tried to buy a Thirsk to Northampton SVR at peak times at the ticket office in York? If the ticket is 100% valid then would the staff be techincally be supposed to suggest this, as I believe they're meant to suggest the cheapest valid ticket according to ATOC rules?
Incidentally I do this quite often on the Thirsk to Thornaby, as I get a ticket from Thirsk to Dinsdale (fare flow calculated via Darlington = cheaper, but via Thornaby is a valid route)
Also, at peak times it often saves money to extend the ticket to get a more lenient restriction code - For example York to Northampton is not valid before 0930, Thirsk to Northampton SVR via not London is unrestricted. What would happen imagining there were ticket checks walking into York station if I walked in with one of the latter tickets , or if I tried to buy a Thirsk to Northampton SVR at peak times at the ticket office in York? If the ticket is 100% valid then would the staff be techincally be supposed to suggest this, as I believe they're meant to suggest the cheapest valid ticket according to ATOC rules?
Incidentally I do this quite often on the Thirsk to Thornaby, as I get a ticket from Thirsk to Dinsdale (fare flow calculated via Darlington = cheaper, but via Thornaby is a valid route)
I think your best bet is to ask on a case-by-case basis, unless the station you are getting off at is clearly on a permitted route to the destination on the ticket and it's either an Anytime or the return portion of an Off Peak ticket, in which case it is permitted.