I general, based on these issues with cancellations and advance tickets, which really could end up being the future with the announcement that LNER will get rid of off-peak tickets, which could go national were the current government to pull and upset and remain in power, I think that terminating at Fratton is simply a bad idea. While it is the busiest, Portsmouth has for a number of years been one of the cities which doens't have a single station that dominates passengers by far. Portsmouth & Southsea used to be (until around 2005) by looking through old stats, but more recently, Fratton, Portsmouth & Southsea and Portsmouth Harbour have all had very similar passenger numbers. I have often thought that terminating at Portsmouth & Southsea as it is is one of those weird things, particularly since Portsmouth Harbour at the time the busiest, so its essentially serving all stations except the busiest (pre-pandemic). I've since looked into further stats and other information (including technical information), and i do get it more now, but based on that logic, terminating at Fratton is just ridiculous, because it only has around a third of all passengers in Portsmouth, while if you include Portsmouth & Southsea as well, you do at least serve around two thirds of all passengers in Portsmouth. I get why you can't serve Portsmouth Harbour however, simply because theres probably not enough capacity. In addition, the journey times will be long enough, so they'll get a bit more turnaround time at Portsmouth & Southsea. In general, I think Portsmouth & Southsea is the best option, and a direct, albeit slower service to Brighton, in exchange for a better service to London, and no loss of services to Littlehampton now (which isn't really a Portsmouth commuter town as it is a Portsmouth visitor town, so not so important compared to Brighton). In general, I was hoping this type of U-turn would be made, particularly when Network Rail said in that 2020 report that such a service (Brighton to Portsmouth & Southsea (presumably)) was feasible. While the loss of London Victoria services in Southampton is a slight loss, its already impractical as a viable alternative to SWR anyways, and running for Gatwick Airport only is obviously not viable) In general, this should be implemented, and I look forward to hearing more possibly.