Distinguishing SUSY scenarios using τ polarisation and tildechi⁰₁ Dark Matter

We discuss first a method of measuring $\tau$ polarisation at the ILC using the 1--prong hadronic decays of the $\tau$. We then show in this contribution how a study of the $\tilde \tau$ sector and particularly use of decay $\tau$ polarisation can offer a very good handle for distinguishing between mSUGRA and a SUSY-GUT scenario, both of which can give rise to appropriate Dark Matter.