I had my test on Sept 26 in surrey and have still not heard anything yet. When I called cic they said it could take 4-6 months. It seems really inconsistent. One friend of mine had her test on Sept 28 and had her ceremony a couple weeks ago. Hopefully we will hear soon.
My wife called CIC yesterday and they said it could take up to 6 months after the test so wait for 2 more months and if after 2 months you don't get oath ceremony then call us back.
I think it varies case to case.