This will kill off the route. Same happened with the NCLSTN. They changed the schedule so there were of no use to anyone, and then the route was dropped.
The drive NCL-BRS and the train both take around five hours. Given travel to airport, check in, wait, board, fly, arrive, bus to city (adding £14 return), then it's not surprising that it's difficult to compete with the train on a city centre to city centre basis.