Wouldn't have appeared at my place, Drivers should get an email , but that's hit and miss too.
Communication to drivers is, frankly antiquated and needs root and branch change imho.
Which they aren't at weekends.
Late notices are still sent in bulk to remote locations and printed off next to the signing on points. RHTT can run over a LOT of separate routes indepdent of where TOC services run to-from. It would be incredibly difficult, if not impossible to advise every driver on every route affected about the potential for issues. The best place for it would be on a late notice (so it is a blanket piece of information) and for drivers to apply leaf fall driving policies, including notifying the signaller of reportable conditions. I wonder if the previous driver through SY31 reported any problems; how long had passed between 1L53 and the previous train?