Ok another note is there a plan to improve information in disruption?
Yes - and it's an ongoing process, but it's fraught with difficulty..
TrainSplit only notified me if this by app notification, I received no other communication on the matter, by email or otherwise.
As you've observed, Darwin changes are currently communicated to customers via app push notifications which
are suited to this sort of time-sensitive messaging (with emails you have the risk of greylisting and much .. less assurance that the message will be delivered to the customer promptly). Darwin changes being communicated at all is in itself a (fairly) recent enhancement! Raileasy was one of the first adopters of the Timetable Comparator Service, too. There is clearly room for improvement here, but it's going to take work (and not just in-house).
There
are desires to offer a "What can I board with my tickets?" service, but one of the biggest barriers for doing this during disruption is the complete lack of machine-readable ticket acceptance data. My personal view is that - at present - industry doesn't fully understand the need or value of this (or frankly, structured data in general). Indeed, sometimes TOCs prefer to keep ticket acceptance "under wraps" and pretend it is not in place.
There is also a lack of clarity on passenger entitlements during disruption; industry workstreams are trying to tackle this but progress has been slow and an NRCoT amendment is not going to happen imminently.
The way I'd
like for this to work in an ideal world - and I've said as much to the ORR - is that when there's a train cancellation, the customer can simply be emailed/pushed a new re-planned suggested itinerary which they are guaranteed to be permitted to travel on. The retailer should be given the business rules (agreed with train operators) to be able to implement the journey re-planning and should also be kept up to date via some sort of pushed electronic messages relating to ticket acceptance arrangements.