Be final: propose that location has area reduced by 50 per cent (5,2,3,4)
I believe the answer is:
bring up the rear
'be final' is the definition.
(to bring up the rear is to come last)
'propose that location has area reduced by 50 per cent' is the wordplay.
I cannot quite understand how this works, but
'propose' could be 'bringup' (to bring something up can mean to propose it) and 'bringup' is located in the answer.
'location' could be 'rear' (rear is a kind of location) and 'rear' is found within the answer.
The remaining letters 'the' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bring up the rear that I've seen before include "Come at the end" , "come last" , "Trailers do" .)