Post your question in the discovery forum and you will get a better response.
Lists all the symptoms, i.e. flashing m+s lights , what about instrument panel and central console lights, limp home mode, is it all the time or if you switch off and back on again does it go away, does it come on when you switch on and select r or d or does it happen when driving.
The easiest way to find out is to have fault codes read.
Do not be talked into buying a new xyz switch even if fault codes indicates this is at fault as there are other problems that can cause this fault that need to be investigated first.