How to Vauxhall (Opel Corsa c, 1.6 Sport, 2007) Flickering Interior lights when car is started

So i had this interior pulsing lights problem and thought to share this with you all.

when the Car is not started the main cluster and interior lights do not pulse, but as soon as i turn over the car and have it idling the lights start to pulse. (dim and bright).

i had the battery checked and it was in perfect condition.

all fuses checked, all in great condition.

went as far as to buy a multi meter and test the current on my battery when the car is off and when it is on.

Main Problem: regulator on the alternator was faulty.

bought a new one and fitted it.

started up the car and no battery light was showing. (all clear readings, and no warning lights)

and best of all, i'm no longer driving in a disco.