  Cavity design using traditional mesh based numerical means (such as the
finite element or finite difference methods) require large mesh calculations in
order to obtain accurate values and cavity optimisation is often not achieved.
Here we present a mode matching scheme which utilises a globalised scattering
matrix approach that allows cavities with curved surfaces (i.e. cavities with
elliptical irises and or equators) to be accurately simulated allowing rapid
cavity prototyping and optimisation to be achieved. Results on structures in
the CLIC main
