Some very interesting reading about how a small slice of this has been going in this document:AIUI, the cross country paths are largely coming back in the timetable changes that are being worked on now. Arriva will know this.
I must say I find this one very odd, IMHO.
For anyone wanting to see the full context it's available here, scroll down to item TTP2570 on the left. https://accessdisputesrail.org/accessDisputesCommitteeIndex/TTPDeterminations/#gsc.tab=0
All in the public domain so not sharing anything confidential...