Then essentially anyone can see that boring colour (3)
I believe the answer is:
hue
'colour' is the definition.
(a hue is a colour or complexion)
'then essentially anyone can see that boring' is the wordplay.
'essentially' says to take the centre.
'anyone can see' becomes 'U' (short for Universal film certificate).
'that boring' means one lot of letters goes inside another (to bore something can mean to drill into it).
The middle letters of 'then' are 'he'.
'he' going around 'u' is 'HUE'.
(Other definitions for hue that I've seen before include "Tinge" , "General hubbub - . . . and cry" , "Tone, shade" , "Tint, shade" , "red or black, say" .)