There's a seat for each honoured companion (5)
I believe the answer is:
perch
'there's a seat' is the definition.
(perch is a kind of seat)
'each honoured companion' is the wordplay.
'each' becomes 'per' ('per' can mean for each).
'honoured companion' becomes 'CH' (Companion of Honour).
'per'+'ch'='PERCH'
'for' acts as a link.
(Other definitions for perch that I've seen before include "What angler may catch" , "Roosting place" , "bird comes down on" , "Bird's seat - fish" , "(Fishy) pole where bird sits" .)