I was very, very young in 1972, if that helps...
Actually, my pre-late-Tom Baker-era knowledge was pretty much non-existent (my parents didn't approve of children watching Doctor Who until they'd produced enough of us and we'd grown to a point where we could band together and protest) until I met DH, who has embarked on an extensive re-education programme of weekend morning UK Gold (Jon Pertwee and earlier Baker, plus some Peter Davidson where I can say "ooh, I saw this one"). I think at some point he expects me to sit an exam...