In reply to Cheese Monkey:
Hi. There is loads of sport climbing all over the country. June is not a bad time to climb as the weather is cool but not too cold. Winter in SA is pretty mild, a bit like spain.
Boven is an excellent spot near(ish) Joburg. The western cape (cape town) area has loads of sport climbs of all grades. In the city there are many areas like silvermine, the mine, peers cave and kalk bay, etc. You also have sport in the rocklands as well as bouldering. There is also montague (about 1.5 hours from CT). They are all ace areas with loads of routes. Check out the SA climbing database:
http://www.climbing.co.za/wiki/South_African_Climbing_Wiki
On the note of the sardine run/dive trips, my bro's wife organises safaris, accomodation and can organise trips like that (as far as I am aware) for folk visiting SA and other parts of africa. I could put you in touch if you want to organise something. Feel free to PM me with any questions
Hope you enjoy the country and your honeymoon