The class-based tutor-led Level 1 and 2 courses typically run over two days. Ideally you will allow three or four months before moving on to the next level, so you have time to internalise what you learned over the two days.
The Distance Learning Programmes, on the other hand, include all the personal experience that you need. You would be well prepared to attend the next level right away.
Aside from that, and assuming there is a choice where you live, it comes down to personal preference. If you mostly prefer working alone and in your own time, a DLP will allow that. If you prefer working in groups and discussing things with others, a classroom-based course will usually be the best option.
Level 3 in a classroom and Level 3 DLP mirror each other more closely. Both involve working with a settled group of other students, and with a trainer and assessor. Both involve work done from home. Both include an assessment process that includes personal feedback, case studies, and a test of your remedy knowledge. With Level 3 it really comes down to what works best for you in terms of being able to travel, and how easy it is for you to reserve a few hours a week for several weeks (in the case of the L3 DLP) to take part in group work online, or be away from home for a longer block of time, typically four days, in the case of the classroom course.
All the DLPs require internet access and relevant computer skills; those are not needed for the classroom courses.