After locking the car you can see ( at night ) that the hazzard warning light flickers and stays flickering untill you unlock the car , any idea's

Try a search as this has been discussed before.

I thought someone mentioned that it was a sign of a dying battery?

Is this on your Roomster or do you have an Octavia too (you are in the Octavia MkII forum).

Roomster now gone , my car now 2012 OOctavia se , 16tdi

Id update your profile from the roomster to the octy,a 2012 car will be under warranty so id pop it back to the dealer,even a battery should be covered at a year old.