Hi Growler,
just seen your post, in my experience there are very few reliable building contractors in the natal area, the main point you must remember is never pay in advance of the planned work program, they all want 50% up front if it is a small one man band type builder, larger 'companies' will have official looking contracts drwan up with staged payments in line with progress of the work, these do not work either, as they always get their plan wrong and never keep up to schedule, which results in the usual " we need more money to pay the workers as this is taking longer than we planned" even with specific clauses in the contract stating that the payments will only by the chronogram, they never do it and then threaten to stop work if you don't pay more than the agreed staged payments, I am speaking from personal experience, there are two companies who I would advise all to avoid for the reasons stated above, these are one from Natal called Misula Construction and another from Pipa called Pipa Pools, the latter being run and owned by a German, which may lead you to think it would be at least efficient, but the truth is the guy is totally incompetent and has no idea what he is doing and employes whoever will work for him regardless of their skills or in the majority of cases lack of skill.
The only way you have a chance is if you are going to be here personally to oversee every single days work, this is sad but true, trust none of them, if you cannot be here then my advice is forget it, you will save yourself a whole lot of grief and a substantial amount of money.