Quiet bells make bizarre instruments! (4,7)

Dead Ringers?

Exactly

Been too busy trying to solve your other one in the TV section!!

Jackie Chan's sport car? (4,2,5)

Kung Fu Panda

Just for a moment I thought you were saying the Fiat Panda was a sports car .. but of course Jackie Chan's sport = Kung Fu and car = Panda

Offered a cuppa but declined?

No letters given, that would make it just too easy

haha my sick mind came up with porno (pour-no) lmao XD

Tino (tea? no!)

Valen tino?

Tino is very close ... think of a more Northern way to offer Peter Kay (say) a cuppa...

Very recent film

Bruno!

(Brew-no)

Yep.. your go

Seth angry about adding chromium to food, making it unsuitable for eating

Seth angry = anag? => The S________

Adding Chromium = Cr? to a food

Whole title clue = unsuitable for eating?

The is correct, S needs to be moved, CR is right....

Just need key word for 'food (making it) unsuitable for eating'

(3,11)

The Incredibles !

The - s
cr
in-edible

clue - servant to Sir Trevor MacDonald?

Batman Fortrevor

Actually, although I was joking above, one of the Batman films is The Dark Knight isn't it?!

think that's right so....

Frank predecessor had a bad smell and was a love cheat

which was correct

Borat

Frank = Bruno
Bruno predecessor = Borat

Bad smell = BO
Love cheat = rat

Would have liked to have seen you clue the full title!!!
"Borat: Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan"

12-1 Shot

I don't know which would be harder - to clue it or to solve it!

Re: the newie....like the gambling parlance wordplay....

12 obviously brings dozen to mind....dirty dozen?...nah, dirty doesn't really tie in with shot (unless you 'bite the dust' maybe)....is there a film called The Deadly Dozen or am I imagining it?

There may be but that's not what I'm thinking of

Don't think of the actual numbers, more what they might represent...

Long Odds would be one answer.

Outside Chance would be another one.