Switchbox
All Silver Cloud I and Bentley S1 and early Silver Cloud II (Prior to SXC1) and S2 (Prior to B2CU) models were fitted with switchbox UD1285. There is an exploded diagram of this switch box here
All internal parts of the switchbox are the same as the switchbox UD5871, which was fitted to the later Series 2 models and all Series 3 models, which is shown here: