There used to be short platforms/sidings at both north and south of the station on the central 6 side. The southern one used to be the parcels bay. The North one probably would have been ideal for a shuttle service to the CBS.
Unfortunately bad planning in the first instance - a X-over and appropriate signalling either end of the CBS station could have meant a shuttle service between Cov - Cbs and Nun - Cbs with the right planning and train stock/drivers etc. But if you notice the normal service on that line quite...