Im not sure thats true anymore. I can find the fares on both BR Fares and national Rail. National rail gives me a choice of any other TOCs site or Tramline. Ive just booked a southeastern advance on Grand Centrals website. I think maybe the bottom line is that services like Raileasy don't want to sell these tickets and trainsplit falls foul of that.That is not TrainSplit's fault; Southeastern doesn't allow other TOCs or 3rd party retailers to sell its advances. Some booking engines chose to break the rules and ignore this constraint (e.g. Trainline), but they have the muscle to do so and to get away with it!