I started on the 8th of August. I haven't had exactly one a week due to holidays and sickness but I'm only just starting on roundabouts. This is because my instructor knew not to start something new until he was sure I was 100% confident on the first stage of his syllabus. (Right turns, left turns, stopping and starting, clutch control, hill starts, traffic lights, cross roads, more complicated right turns, busy traffic, open and closed junctions, creeping at junctions, tight turns, going up and down gears, giving way etc)
There is no point moving on to something new if you can't do it correctly. This is why there are so many new driver accidents because people are rushed through learning, enough to pass and then can't actually cope on their own!
Ask your instructor about it, he may feel that you are not confident enough on roundabouts yet to move onto something else. You can always ask him how he thinks you are doing, what needs working on etc.
Or if you truly feel he is taking the piss and milking you then move on to someone else!