There are some electricians on Houzz in SA (https://www.houzz.com.au/professionals/electricians/s/Electricians/c/south-australia) Best to contact a handful to compare and see what the going rate is in your area

your lighting plan sounds great and the floor is gorgeous but hope you plan to add some screening to the top of the fence and perhaps some tall bamboo or similar in narrow pots to help with privacy

It looks like an old coach light, my grandmother had almost identical ones on her front porch, they have upped the anti on the design, it may be hard to find, maybe try antique stores.

The most common outdoor light fittings are floodlights, up/down wall brackets, garden spike lights, and bollards. When selecting lighting for residential outdoor areas, it is important to select fittings which will provide security and will withstand weather conditions. You need to use lights which have an IP rating, meaning they will resist weather elements in outdoor settings. For luminaires which will be used under the eaves of a roof, a minimum of IP44 or higher is recommended. For pergolas, a fitting with IP54 or IP65 is needed. For fittings that are fully exposed to the elements, an IP65 rating is highly recommended. To ensure that your light fittings do not rust or corrode over time, opt for high quality brass fittings with a powder-coated finish, or a marine-grade stainless steel. In garden lighting, low voltage 12V fittings are recommended in order to prevent electrical hazards. For this, a transformer is required to convert the 240V mains supply to a low voltage for exterior garden lights. Wall brackets can be used to highlight brick or stone textures on the wall. Garden spikes can be used to up-shine key features like trees, fountains, or statues. To find out more, visithttps://elekzon.com.au/blogs/news/your-design-guide-outdoor-lighting