I get the impression that the FAL-HB was like Marmite (or Vegemite), you get the odd Whenwe waxing lyrical about the ones South Africa sent there, but then another won't have a good thing to say about them.
I imagine weighing in at 13lbs to the Bren's 22lb probably won it a fan or two, but its bang-bang-click reputation probably cost as many.
My only comparison is between No.4 Lee-Enfields, L1A1 SLRs and the Sterling, so I have to take sage advice or BS from others outside of such limited experience.
My memory may be slipping but I am fairly sure that it was the AR18 that Sterling produced for us under licence.
Just checked various websites that agree that Sterling produced the AR18 and AR180. Some units did use the M16 (AR15) later as I said.
You're both right. The AR-15 was used first in Borneo/Malaysia in '65, followed by M16A1 shortly after and thereafter. Sterling got the rights to the AR-18 in 1974 and while the British Army bought some, Malaysia and Singapore were the biggest customers after the U.S. wouldn't sell them the M16.