This was on BBC» South this morning. While the SWR» suit only promised a new, cleaner, future for hie trains, Paul Clifton, the voice over, and the studio introduction all made that specific claim about SWT▸ . They showed a "deep clean", though it didn't look so very deep to me, saying there hadn't been one for ages. But surely it takes more than six months to get a train that grubby?
This evening's BBC South introduction quantified a "deep clean"; SWR say they do one every 30 days where SWT did them every 210 days. (That's longer than from franchise announcement to end, of course.) Sounds more like part of a routine cleaning schedule to me, but it's still rather childishly "cleanlier than thou".