Dear Paul,
Seldom there are other traditions that do Dorje Shugden practices as well. However, the practice of Dorje Shugden can be also practiced with other practices if we are doing them. The image of Dorje Shugden can be placed on the same altar as other deities of different backgrounds.
I think you can go over to the NKT first, if you really do not like it, then change a different centre is fine.