I would avoid film type finishes on outdoor furniture, it won't be long before they start to peel. Some species don't need any finish but they will generally turn weathered gray after long exposure. Don't know what is available in South Africa. There are numerous deck finishes in the US that will be much easier to renew and offer decent water resistance and UV protection. This site carries a lot of different products, maybe some are available to you. http://www.opwdecks.com/