@Grant Rhino
That's so awesome that you've been to Sri Lanka and seen PF Langurs in the wild, really really cool.
I 100% agree with you about it being a travesty that they were kept off-display at PZ for so many years. I couldn't fathom why the heck they chose to keep them away from public viewing in the end.
Tetrapod explained on another thread about why they were phased out of the zoo: rapid loss of individuals (think initially was just a pair) and the remaining two were an elderly female and young male (the ones who were exported to Edinburgh Zoo in mid '05) and the region wanting to focus on Francois Langurs (though Perth has never acquired that species, and Adelaide has continued with Dusky Langurs which am very impressed with).
I agree with you, passionately believe that PZ should of still kept their last two PF Langurs on display prior to export (in fact they may have even gone off public display earlier than mid '99, I mentioned mid '99 as latest time possibly on public display still as that was when 'Gibbon row' was closed off to the public but remained as holding pens for off display primates until its demolition in '04, but some primates were perhaps also kept in another off-display area that was already away from public-eyes in the '90s. There also was Tonkean Macaques, B+W Colobuses, **Vervets, White-Fronted Capuchins and White-Fronted Lemurs held in staff-access only areas of PZ at various times in that era of late '90s and first decade of '00s (think so frustrating that public couldn't see some of them in their final years at the zoo).
**do have memories of still seeing some of the Vervets in the Lesser Primates precinct
in early-mid '00s, perhaps some of the Vervets were separated from the main group and help off-display. One of our ZC comrades mentioned that the Vervets at PZ had just had a new baby born in their group in early '06..but later that year were all sent to Gorge Wildlife Park in South Australia regardless.