does it really make a difference if a tv has 24 p ?
surely a dvd or blue ray for this region is 25fps?
would the source have to be 24 fps for the tv to play at 24fps?

Yes but the level of difference will depend upon how sensitive you were to panning judder when viewing content that was frame rate converted.
R2 DVD's are 25fps but Blu-ray are virtually all 1080p/24 so they match the production frame rate (film and HD video), it's pretty much a global standard now.

So a modern well spec'd HD telly will fully support 24p sources at 24fps (multiples there of) while also accepting 25/30 frame rate material and quite frankly any decent large flat panel should handle 24fps correctly these days.