Googlebase Feed - Adding a custom attribute for 'Condition'

Hi,

This is my first post on these forums so go easy on me!

I have recently installed Opencart 2.3.0.2 moving from a very old oscommerce site. So far, I am really impressed!

One thing I was hoping someone could help with is the googlebase (merchant) feed.

On my products I have added a custom attribute 'Condition' and have entered either 'New' or 'Used' when listing products. I was hoping I may be able to edit the googlebase feed to pick this up, rather than it passing 'New' for every product.

Can someone help with the code I need to change to make this happen?

Many thanks, Lee.