I just went to my old church's website and found out what they're up to.
When I was there, the midweek home Bible studies were called Cottage Meetings, then Home Groups. You studied pretty well what the study leader had on his (or her) mind at the time. The Church Growth Movement of the late 80s and 90s has changed all that. Looking for the secrets of success in growth led the leaders of the movement to look even to the cults - apparently "bums on seats" was more important than strong theology.
So what is the shape of things now? The midweek meetings are "Cells" and you must attend your local one, not the one your mates attend. What you study is exactly the same thing that everybody else across the board in the church studies that night, regardless of levels of maturity, etc (meaning that it is a lowest common denominator exercise - the milk, not the meat, of the Word).
For an example of what the "Cells" study, see:
http://www.smewebsite.com/lighthouse/htm/weekly_studies_sub.htm