Thanks Richard.
I already tried JB Sports Engineering. Billy Bellinger hasn't got any 3HA bits but he will keep any eye out with his contacts.
I'm still searching elsewhere. Last night I came up with a possible option for a 4 Star replacement center or an LSD that will fit. The 4 star center is "unbreakable" but both options come at a hefty price.
Considering the fact that there was 3 broken teeth in the diff housing when I pulled it apart and the there was only one pinon mate gear tooth missing, it must have been an ongoing problem.
Cheers,
David.