Hmm.. I am speculating....
It could be because of the "manpower" crunch during the 90s...
because of falling birthrates....
Also during that time there was more emphasis on NSmen being
"operationally ready".
So maybe they decide to cut out one active Gds Bn and then maybe
use one NS Gds Bn as the 3rd Bn for the 7th Gds Brigade.
Initially the different units like 1st, 2nd, 3rd Gds and HQ 7th
Brigade are in at least 2-3 seperate location.
I think there was a move to centralize them.... i think now there
are all in Dieppe baracks the ex-home of the kiwi 1st Infantry
Bn.
So i guess during the time where they move the Gd Units, somehow
2nd seems more convenient to disband whereas 1st and 3rd are
centralized together with the Brigade HQ.