Maybe I am showing my ignorance here, but BRENT-LW crosses just to the Western extremity of R157 - and according to my map from Mauve 134 - means you are clear of R157 with 1.5 miles to run to the LS.
Therefore, given the extra track mileage for a right/left base final (not massive I will concede) means that you have about 2miles to drop from 1401 feet to landing.
Is that unworkable?
Again, showing my ignorance, but can you not make 1401 feet after 1.5-2nm from take-off?
I am sure there is someone here who was around when the specified area came in to play. (apart from ATCO Two!)
Interested to hear how that was dealt with. (when was it brought in??)