Marriage

Hi everyone,
Just looking for some up to date advise as I found some previous threads on what I need to do to get married in SA to a South African but they were a few years old.

I'm due to get married in August and so far I have figured out I can go in on a tourist visa and then go through the interview process 60 days before getting married.
What I need to know is information about this certificate of non impediment. I have been advised that the UK do not issue them for marriages in common wealth countries, and that I can pick up a letter from the consulate in Pretoria to state this. What do I need to replace this? I've read conflicting information that I can go to a police station and have an affidavit provided by them to say that I am able to marry, is this still correct? I was previously married but have all the paper work to prove that the divorce was finalised.

If someone could let me know that would be great as this process is really stressing me out something awful.

Thanks so much.