Last time I used trains with slam doors semi-regularly was early 2000s, when Manchester - Scotland services were still loco-hauled (then replaced with shorter, more overcrowded Voyagers, which in turn were replaced with even shorter, even more overcrowded 185s). I'd have been in my 20s then. At any rate I assume they were slam doors, I can't remember the doors but AFAIK no-one had converted any loco-hauled stock then, but I couldn't even tell you if they were Mk2s or 3s.