Distance Learning Courses

I didn't do as well as I could have done in my A-level Geography so I'm thinking of retaking my exams for this subject, I'm also thinking of doing a whole Biology A-level in a year on a distance learning course but I'm worried about not having the motivation to make myself learn the whole course by myself without teachers guidance, Has anyone had any experience with this kind of course? How did you find it?

Another problem with the A-level distance learning Biology course it that it comes without a practical endorsement so if I decided to pursue this subject at degree level I'm worried I wouldn't be accepted onto any courses.