The distance learning courses are not entirely distance learning, they require a minimum of 65 hours to be completed in the classroom.
My understanding is;
ATPL theory requires 650 hours of 'ground-school'. This is done in
either a classroom or at home (DL).
if done residential this is not a problem.
if done via Distance Learning
a percentage (10%/65hrs?) of that training must be done at a suitably licenced school. This is covered by the 2x2 week 'refresher' immediately before each batch of exams. The service provider will sign to confirm that the remaining hours have been met by the candidate 'off site'.
Just my take, could be complete
though!