I don't see why the railway should just write off the restrictions they accepted on their £5 fare
The restriction, as far as most people are concerned, being that you have to take the booked train.
But when the railway is at risk of reneging on its side of the deal by cancelling the train, it should do everything reasonably its power to mitigate the delay, including allowing people to travel on other TOCs and routes. That would seem a prime example of what might be considered reasonable care and skill.
because they chose extreme thrift by using the railway's competitor from London to Birmingham, to be honest.
What has that got to do with anything? They may just as well be flying out to Spain.
Yes, of course it's sensible to allow some slack when transferring between modes, but it seems little more than victim blaming suggest that the passenger is at fault where the railway has delayed them!
If the connection at London were onto another train with a split ticket, would you, absent the clear position in the NRCoT, be suggesting "well it's their own damn fault for splitting their ticket"?
The upshot of this sort of problem is the removal of TOC-specific fares (which is already stated policy) and alignment of fares at the most expensive levels.
Totally with 'AlterEgo' on this. Whilst these cheaper fares continue to exist, the restrictions have to be followed even if there is a cancellation.
If you happened to hold an Avanti Advance from Preston to London and were booked on a service via Birmingham that was cancelled, you would be allowed to travel on the next service - even if that means arriving slightly earlier than booked.
The same would apply if you've booked to travel on SWR from Portsmouth to London via Fareham. Or on WMT from Rugby to London via Northampton and so on and so forth.
So why should passengers be disadvantaged just because some politician or civil servant in the 1990s arbitrarily decided to split Hastings-London services between two different operators?
This is typical of the attitudes that are so so ridiculous they could only happen on the railway.