Dash lights fault

Dash lights plus radio went out a year ago. One Bristol Citroen dealer assured me that he new the problem and it would cost £840 to fix. Driving home in shock hit a pothole and all lights returned to working order. They have just gone out again. Drove over speed bumps quickly to jault back into action unsuccesfully. Convinced its not a light bulb problem. There was a rattle behind dash last week.
This car a has a mind of it's own. Sometimes rear wipers have been known to come on even when no key in ignition. Also headlamps come at will!
I was warned not to buy a Citroen!!!