Interesting. Before the Elizabeth line was officially opened, there has always been a shuttle service between Shenfield & Liverpool Street, stopping at all stations. I think it went through the usual gamut of failing private sector operators until, quite a few years ago, it seemed to have been adopted by TfL. I'm not sure that they owned it per se, but it didn't have anyone else's branding immediately obvious to the casual observer (me). Has that changed with the official opening?