Originally Posted by mtkeller

The Trainline and many of the train operators use the same system for booking, although the Trainline adds on a couple quid in fees that the TOC don't. I'm pretty sure the constraints you can place on seat selection are identical across the Trainline-based sites. Further, the EC/Chiltern/SE/etc. system doesn't allow specific seat selection either, in my experience. (This is really unfortunate when booking a cheap advance first ticket on EC. As a single traveller, I'd like to get a seat on the single side that doesn't share a table with anyone.)

(Posted from one of those seats on EC. Still waiting for the train manager to come through and check tickets from DEE, even though we're almost to EDB, so that I can pay my £25 weekend first upgrade supplement. Worth it when I need to be working and someone else bought the underlying standard fare. I guess I should get back to working and get off FT )