AusieXJ,
I have fitted an aftermarket one to my 1998 Sport. I bought the barrier from 4WD Systems. Very easy to fit - just two drill holes through each wheel arch for bolts. I would ring them and ask if they do one for your vehicle. Much cheaper than the Milford barrier if you can get one to fit (I think mine was under $300 including postage to Canberra).
http://www.4wdsystems.com.au/
Hope this helps,
Rick