Mystery Loading Screen from unknown mod

UPDATE - SORTED! See reply below for source.

Skyrim SSE/AE. A mod has dumped this image into my game, and overrides my Loading Screens.

I cannot track it. I've search xEdit on the LSCR field, search DDS files until I am exhausted. I've checked through live and inactive mods.

The trouble is, it could be buried as an instruction in an ESP, or even a DLL.

If anyone recognises which mod it came from, I'd be overjoyed. Thanks!