When you say "theatre rental company", what level of production are you talking about? Are you renting to small community or school theatre groups? Are you renting to large professional theatre groups? Something in between?
I saw Rhys reply to your question on the theatre sound list and I think all of his suggestions are valid. It kind of depends on what your production needs are; i.e. how many inputs and outputs do you need to be able to provide for, what level of experience are the operators, what kind of manufacturer or third party support can you get in South Africa for a given brand of console, and how familiar are the operators in your area with that console?
I don't see the SD7 going anywhere anytime soon. It's still going to be on riders for many years after it goes out of production, just as the PM1D and PM5D were.
But the PM7/10 are both worthy contenders I think and can do a lot that the CL line can't, besides just inputs and outputs. I don't know that the Avid S6L has really worked it's way onto many theatre shows yet, or if it will. Touring theatre here in the U.S. seems to be about 75% Digico SD7/SD10 with the remainder split between Yamaha CL5, Avid Profile, and even the odd PM5D and a few analog Cadac J-types still running around out there. Here in the U.S. we never see Midas consoles on touring theatre shows.
