a Milford Haven to Manchester train
What, one train? All the way? In the same day? Took 'em long enough...
It isn't massively strange, but Great Malvern seems a rather small place to regularly terminate long(ish)-diatance London services; I'd guess Worcester has too little space and Hereford would need too many more resources to serve hourly?
It's not that small, especially if you lump Malvern Link in with it; it's the main origin/destination point beyond Worcester, and it has long been common for a lot of services through Worcester to terminate there, wherever they go on the other side of Worcester. Then, Malvern to Hereford is about twice as far as Worcester to Malvern, and apart from Ledbury station it's all single track, so there isn't the capacity to run more trains all the way through. And it's less important for Hereford passengers as they have the alternatives of going via Shrewsbury towards Birmingham or via Newport towards London, so there are fewer who actually need a service via Worcester.