Here’s some information for you poor buggers trying to get to Bournemouth by train next week if you want to avoid the ghastly bus replacement service/non-service :
My suggestion is to catch the train to Fratton from Brighton or stations en route. Change at Fratton for any train going to Eastleigh (South Western Trains or GWR services) arrive at Eastleigh and get connection to Bournemouth or Pokesdown via Southampton. Do the same for return journey.
Trust me, I’ve had to do this on many occasions trying to get to Brighton from Southampton for home games when there’s been engineering works. Best of luck!