Pretty much all the ground school courses require payment up front; this includes all your course manuals and the classroom teaching element required as a brush-up before the exams.
In general, you self-study all the subjects but your groundschool instructors should be on hand via phone and email to help with any questions. Then just before your exams, you go to the classroom where you will spend a day or so on each subject. However, the school to which I went did not do brushups for Air Law or Ops Procedures as these are "read and remember" subjects. All JAA groundschool courses have to have a classroom element (unless you are exempt by having an ICAO ATPL already). However, you either have to enrol on a full-time residential course or distance learning - not sure there is the facility to mix and match.
You you go the distance learning route and you want extra one-to-one tuition before the brush-up course, then you will probably have to find a private tutor.
Cheers
Whirls