It took me 18 months in total. I was working a six on, three off shift at the time. Levels off study did depend on where I was on that shift. Towards the end of a shift it was quite tiring and sometimes better to take a night off so that the next may be more productive. Also, I did run a scout troop during the first year of study until it became clear that something had to give...
Each module took 9 months of the 18.