I've noticed that on SBB, whenever a train is announced the announcer usually mentions, if it's an InterCity train, that passengers for coaches 1-4 should wait in Sector A (designated on the platform), passengers for coaches 4-8 should wait in Sector B, and so on, while passengers wanting access to the bike space are told to wait in a certain sector. This means that passengers with reservations know where to wait on the platform to avoid a last minute rush down the platform to the carriage where they have reserved seats. It also means that boarding times are sped up since passengers with bikes, wheelchair passengers and passengers with luggage, since they know where to wait, can get on board more quickly.
This should be adopted in the UK now that more and more passengers now buy advance purchase tickets with compulsory seat reservations. There's nothing more annoying, especially if you have luggage or a bike, to wait on one end of the platform, then as the train pulls in you discover that the carriage you want is at the other end of the platform; something that's happened to me on more than one occasion. It shouldn't be too difficult to implement, since all that needs to be done is for sector markers signs to be installed and for a few announcements to be re-recorded.