Waterloo isn't at capacity though. There are times during the day when trains can't stop at Clapham Junction but that's on the mainline side, not the Windsor side.Absolutely, clearly the signaller hadn't had their coffee yet that morning.
However, still think it's madness to allow a charter in to Waterloo in the morning peak. If there are spare paths (which again is surprising given we're told Waterloo is at capacity) then SWR should be using them for extra services.