TSW took the ITN Big Ben programme just before midnight (before Westcounry came on air) so presumably Channel did its own thing then took the ITN programme via TSW then went back to doing its own thing.
Channel was taking Rowridge, not Stockland, by that time Steve.
They'll either have done their own thing (extremely unlikely after 23:00 and, effectively, on a Bank Holiday) or just taken the TVS into Meridian feed (much more likely), but I don't specifically remember.
Channel weren't doing very much after 23:00 on any day by that time. Once TVS introduced Late Night Late, Channel just took the feed overnight. Even the station ident at the end of Late Night Late and before TVam was generic, rather than TVS. The wording was "You're watching Independent Television for the south, the south-east and the Channel Islands".