Channel 4 the new home of FTA Formula 1.

No, always has been BBC/Channel 4 since around 2012, even at races where Channel 4 aren't live. Sky aren't likely to offer their coverage to a direct rival to their services (Sky Sports F1 available in the Republic of Ireland) No build up or features, just the commentary from 5 minutes to go to session start to end of session.

didnt realise channel 4 did the world feed too, I always thought it was Sky.

All broadcasters take the world feed which is controlled by FOM, they just stick their own commentators over and other broadcasters can take it if they want.

Setanta did originally have their own commentators, but they gave that all up a few years ago (around 2012, as mentioned above) and moved to taking BBC commentary.