@goatsarah I haven't ridden a UK train since the before times[#] but the problem with connections in the UK is usually the other way round - "there's only four minutes for this connection, will I really be able to find the right platform and get their with my luggage?"
To which the answer is usually "yes", because the timetable has been designed that way, and they'll often wait until the stragglers have made it before releasing the new train.
[#] Apart from a couple of short rides in nearly-empty trains on tourist lines.