Hi JonnyP
this is my experience: I got the skills assessment as professional civil engineer on August 23th (6 years experienced, Engineers Australia requires 3 years at least). Nomination lodged on September 30th, Visa on October 14th (Direct Entry, Low Risk, 3 people). My IA told me to wait about 5 months before asking him updates. Yesterday (after about 5 months) he asked the employer further some work paper and my signature on a document. I asked him if we're close to the goal...I'm waiting for his news.
I advise you to lodge the visa demonstrating 3 or (better) 5 years in order to avoid any assessment problem.
Good luck to all of us!