Tracsis seem to provide (using a subset of brands "Iblocks, exposure, TTCS") Delay Repay to operators I've not even heard of:
c2c
Thameslink
Southern railway
Transpennine Express
Great Western Railway
Avanti West Coast
Scot rail
Greater Anglia
East Midlands Trains
West Midlands Railway/London Northern Trains
Hull Trains
Southwestern Railway
Transport Wales
Maybe more.
Given a link I shared earlier talked about preventing "cross TOC fraud" - Tracsis seem to have a system that can share data even with other operators who aren't in the list above. It does caveat with "where data sharing agreements exist", which implies (to some extent) that some data sharing agreements already exist. From a legal perspective you probably don't need a data sharing agreement to share within the same "group" - as long as it is in the privacy policy like Abellio.
I did a "google" and found an actual Data Sharing Agreement for Northern and "First Group"
here - and some of the companies above look like First Group companies on the face of it, although I defer to you guys on that point. It therefore seems probable that all these claims are being shared between all of the operators on a large national scale. The rationale is:
Which would tie in with people getting letters around now - as COVID seems to be the factor. Not sure whether that's people claiming now when they have stopped travelling (and now dodgy claims are standing out like a sore thumb), or it's given them a chance to slow down a bit and take some time to implement technology during the quieter period.