At the rest centre, journalists have nothing but coffee (8)
I believe the answer is:
espresso
'coffee' is the definition.
(espresso is a kind of coffee)
'at the rest centre journalists have nothing' is the wordplay.
'at' means one lot of letters go next to another.
'centre' means to look at the middle letters.
'journalists' becomes 'press' (I've seen this before**).
'have' means one lot of letters go next to another.
'nothing' becomes 'o' (looks like zero - 0).
The middle of 'rest' is 'es'.
'es' next to 'press' is 'espress'.
'espress'+'o'='ESPRESSO'
'but' acts as a link.
(Other definitions for espresso that I've seen before include "Drinks machine" , "Coffee made by forcing steam through grounds" , "that's stimulating" , "Strong black coffee" , "Kind of shot" .)