Also, you might run into a problem where the shower arm is too short or angled too sharply for the shower head you bought. This can happen more with the wand-type shower heads and the wall gets in the way of the wand. You can solve this problem by making sure you buy a shower head that fits or installing an extension arm onto the main shower arm. You can find those the same place you buy the shower heads.
If nothing inside the home was altered you should not be getting a smell. Personally I'm confused as to why the repair person would have left the original line there and ran another one through a new hole. I would have pulled the old line up, ran the new line (in PVC) and used the same hole in the septic tank instead of creating a new one. Did he seal up the hole in the tank from the old line?
Using corrosive chemicals to dissolve a clog is like throwing a grenade down a gopher hole. Instead, Wroblewski recommends flushing your drains weekly with a half cup of baking soda and one cup of vinegar. Let it fizz in the drain for ten minutes, then pour in four cups of boiling water. Find out about the plumbing nightmares that will make you cringe.
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license