OK, here goes:
Most of SA gets summer rainfall, but CT has a Mediterranean climate so it'll probably be warm/hot and dry when you visit. Summer temps are usually in the 20s but can easily get into the 30s, and it can be pretty windy at any time of year. Just dress for the weather, most of us are fairly casual. The same shoes you wear in the UK will be fine, I'd just bring a pair of "smart" shoes and takkies (sports shoes/trainers). You can get sandals here if you want them. Be careful in the sun if you're not used to it.
Landscape photography: Table Mountain, obviously. There are lots of views from various perspectives, and you can walk up - it's a stiff climb - or take the cable car to the top for more opportunities. Inland, the winelands have quite a "European" feel to them and are quite scenic. The Hex River Mountains are about 75 miles from CT and are impressive. Other than that, the coasts (Atlantic to the West and Indian Ocean to the South East) offer miles of beaches and seascapes. Try Boulders Beach in Simons Town if you're interested in photographing penguins and seals. It's reasonably accessible by public transport, and close to the Cape Point Nature Reserve. Unfortunately this is going to be the wrong time of year for whale watching, but you might see dolphins. Robben Island (Nelson Mandela was imprisoned there) might be worth a visit, and you should be able to get good photographs from the ferry too.
The Garden Route is lovely, and the N2 highway follows the coast most of the way. There are quite a few towns on the way, but I'd skip Plettenberg Bay. It's a popular holiday destination for wealthy people, but most of the resident population seem to be retired doctors and dentists who enjoy golf! The Bloukrans Bridge over the Storms River at Tsitsikamma is the highest single span bridge in the world, and the highest bungee jump. You can access the walkway under the bridge (there's a fee and it's supervised) and get awesome photographs down into the gorge, or drive along underneath and shoot upwards. Knysna is well worth visiting. The Heads (two headlands enclosing a lagoon) are photogenic and you can take a boat ride to them, disembark and walk/picnic in the Featherbed Nature Reserve, and catch the boat back to the harbour; or drive to the eastern Head, park and walk right out onto the headland for seascapes and big waves if you're lucky. The lagoons along the coast and the and the abandoned gold mine and town at Millwood above Knysna are good for photography too. Wilderness (small town) is a bit further along the coast and has a good beach, and the railway bridge over the Kaaiman River is a classic photographic opportunity. Unfortunately the line is closed now, because of subsidence but you used to be able to get shots of the steam trains crossing it, which were spectacular.
The coast north of CT is mainly small towns, which are quite picturesque. Langebaan is beautiful but is getting a bit too developed for my taste. Further north is the Richtersveld Transfrontier Park (mountains, deserts and harsh, with a lonely Atlantic coast) which is excellent for photography but it's about a 500 mile drive. This is about as close as you'll get to experiencing the real Skeleton Coast which lies much further north in Namibia and Angola, and is unbelievable! Getting there involves a lot more travel though, it's expensive and you have to book with one of the registered tour companies because it's risky to do on your own.
I can't really give you any info about the private game reserves in the Western Cape because the ones I'm familiar with are all much further north and in KZN. I'd just do an internet search and look for recommendations, or ask around when you get to CT.
Just ask if there's anything in particular you want to know, and I'll try to help. Have a great trip.
