1997 Renault Megane immobiliser over-ride/ reprogramme?

Please help- cant use my car! The 4 digit code inside my key is 8214 .... have tried repeatedly following instructions to enter this but ends up with both the immobiliser light and ignition light flashing rapidly??
My chassis No. is: VF1BA0F0217013274 .... it would be great if you could confirm what my 4 digit number is.
I also had my spare key mended and re-housed, and though it works with the camera check, it needs reprogramming apparently? So instructions for how to do that would be fantastic, if you know.
Many Thanks