Ok was going to try sort this issue out myself but it's getting on my nerves now!!! Having a few issues, hear goes

1) when I flash at someone the Head unit resets

2) when on idle the lights flicker and dash lights flicker

3) when I go for a drive and return, when I turn the car off if I try turn back on the car tries to turn over but get the noise like battery is dead, however I've just done a 40mile journey and turned car off and tried to turn back on but nothing. Literally nothing. Dash lights come on but that's it...

I've have battery and alternator checked and they said its not charging the battery went to another place and they said its fine so I was led to believe it's temperamental I removed alternator plug and cleans it out also..

Any ideas please!!!