Astra Van Envoy 1.7 TDI Y reg - 2001

Problem of loose connection/bad ignition switch.

1. Would like to remove, firstly, plastic cover over input wires on left hand switch mechanism, to check if just a bad connection or burnt input/output wire connector.
2. Would like to remove ignition switch, left hand side of column, to replace alone, not barrel right hand portion etc, if this is possible.
3. Please could someone provide a step by step method, with images if pos, to achieving the above.

All help greatly appreciated