Quite. The exception being I suppose Cressington: the narrow platform extensions (built for Merseyrail in the 1970s) could accommodate 6-car 507/8s. Even if they had been raised in line with the rest of the platforms for the 777s, they are too narrow to safely accommodate wheelchairs etc. As there are still no lifts at the station no wheelchair users are going to show up there normally, but it must be safer to restrict it to four cars. But without access (except in emergency) between the units, passengers bound for Cressington wlll need to be warned to use the front/rear 4 cars only at every station, unless one door in the second unit can open safely. It rather looks as if nobody thought this through until recently.