Oh my. So anyone trying to use the SW mainline from GWR▸ land to get around there being no long distance trains to London Paddington has been well and truly stumped.
Well, not quite. The via Southampton option is still available as Weymouth to Waterloo trains are diverted via Havant and Guildford today due to planned engineering work, but only hourly. Past experience of travelling on this diverted and reduced service is that these trains are very busy, particularly on a Sunday afternoon/evening.