This assumption that Hitachi AT300 units are the solution to all services just because they are bimode could end up constraining the capacity of sections of routes where local services are provided by rambling regional stock. There is a growing need for (say), 23m EDMUs with 1/3, 2/3 doors to enable such a dual role to be served. Typically, if the Hitachi AT200 was configured as such it might become very useful in many parts of the network where regional services use sections of line where intensive local demand exists.TPE needed the 125mph capability for York - Darlington, there was no provision 100mph paths in the May 22 (now May 23) timetable on the ECML. The same argument couldn’t be used in favour of 810s on Liverpool - Nottingham.
This might be a topic for a separate thread.