The whole process took me a little over a year. That being said, I had delays due to having to apply for finance again (the pre-approval I had when I bought the land had expired, which ended up being handy as my wage had increased).
My site was cleared in August and handover was start of February, so the building process was about 6 months. My house is 19sq and had a few delays with my slab pour due to winter weather.