Sat Tele No. 27,091

[bryand]

3d) Complicated work defeat him? that's not true (4,2,3,4)
12a) Place for marksman soon gathering excitedly (8,5)
24a) Fuel additive in tank, I conk out (9)
27a) Sit angrily suffering sore throat (10)
Thanks for any help

[ubasses]

wide of the mark
shooting range
antiknock
laryngitis

[sandyRoe]

27 laryngitis

[ubasses]

They are all anagrams by the way.

[dannyk13]

3d.Wide of the mark
12a.Shooting range
24a.Antiknock (anagram of tank I conk)
27a. Laryngitis ( anagram of sit angrily)

[Lie-in King]

3d Wide of the mark - anag 'work defeat him'
12a Shooting range - anag 'soon gathering'
24a Antiknock - anag 'tank I conk'
27a Laryngitis - anag 'sit angrily'

[DaisyNonna]

wide of the mark
shooting range
antiknock
laryngitis

[bryand]

Thankyou ubasses, sandyRoe,Dannyk13, Lie-in-King and Daisy Nonna for your very prompt and informative help.