I have seen the very first Doctor Who. Back in those days, one "episode" was really one story told in a series of sort of mini-episodes. Therefore, the very first Doctor Who episode "An Unearthly Child" is actually 2 or 3 showings. There is a YouTube channel called DoctorWhoClassics where you can still see
ONE PART OF THAT EPISODE. Unfortunately, the BBC has now blocked most of the content there. I think I watched up to episode 12 after the defeat of the daleks. I think you can still watch episode 11 (S01E11) where you can clearly hear that the voice of the Daleks hasn't change at all since then. I've also seen about 5 episodes with the 5th Doctor.
I plan to watch more classic DW soon.