We have just vacated a property and are in dispute with the landlord over the return of our bond. He is claiming all of it £575 for redecorating and non working lightbulbs. We are arguing that because of a past dispute we are being treated unequitably. We can make a robust case for this. However an additional point is that having started to look into the issue we have discovered that we did not have a gas safety certificate at any point in our 18 month tenancy, we did not know this should have been in place. What if anything can we do about this and does it add anything to our case against the landlord.