South Africa - Codes & Coupons ?

Hi Everyone , first post. I've read and searched as much as i can but bear with me if i have missed the obvious before posting.

I'm an Avis Preferred customer with one rental under my belt , looking to book 23 days car hire from Cape Town Airport in South Africa in December using the Avis UK site.

My preference is the Medium Compact Toyota Corolla , manual shift and the best price i'm getting is £447 . Logging in with my Preferred details makes no difference to the price and neither do older codes i found on here ( in posts back in January ) for BA Executive Club .

I'm also registered with Flying blue , Emirates Skywards & United Airlines frequent flyer schemes at the basic levels, but not aware of any Avis codes for price discounts for them.

I have tried pricing through the Avis South Africa and USA sites , both are more expensive. South Africa 50% more

Does anyone know of any codes that i can reasonably use ?

I have Amex , Visa & Mastercards but again searching didn't turn up anything.

I could join Costco or similar in the UK if there is a useable discount worth it.

I could try another company, Holiday Auto's was £70 cheaper but they are a broker and i had great service when i rented from the Avis Cape Town Airport branch last year.

Any help would be very much appreciated.

UPDATE - Have searched further around the site and used this code S754600 which dropped the price by £50 when i booked so i am well happy

I am trying to rent in SA, too, and used Costco A108326. It dropped my rental from $750 to $600. In the US, at least, you get an additional driver free, but I need to call and ask about SA in that regard.

QUESTION: When I reserved online, the CDW and theft insurance was automatically included and I could not "uncheck" the box. I have Amex premium rental insurance that does not exclude SA, and I don't want to pay Avis' rate for this additional coverage. What gives?

Also, I want to add LI (liability) and the chat rep said that it was already included, although the reservation does not indicate that. Grrrr.

Any help appreciated.

P.S. Weirdly, I could make the reservation online as a guest but not as a Wizard member. Kept telling me to call.