As part of preparations for the new Super-X divertor (SXD) on MAST, the influence of long divertor leg is modelled by SOL transport codes. The SOLPS5.0 package is used to study the effect of the expanded divertor in two dimensions and a comparison between the conventional geometry (standard short divertor) and the SXD geometry is presented. We focus on plasma parameters in the divertor and total particle and energy balance in the SOL. Finally, a one-dimensional SOLF1D code is benchmarked with SOLPS and used to study the effects of longer connection length Lk and magnetic flux expansion rkB separately.