Hi there,
I've completed an access course ready to start uni in September, also with the Distance Learning Centre, having achieved all distinctions. Years ago when I was in education, I didn't do particularly well in school and certainly not in A Levels, so it was certainly a confidence boost having done well in this!
I would say the main factor for me, was how much time I allowed myself to complete the course, especially if you'll be working alongside it. Although you may not need it, I would advise giving yourself a year to do the course - they give you the option to choose your own start and end date, though the longer the better.
In terms of how easy it was - it really varies in terms of tutor how much support you receive. You receive a materials pack in each unit where you essentially self-teach by reading and testing yourself. You're then given an assessment, in which I was allowed to use the materials alongside. Then, depending on the subject assessment, you either essay write or provide shorter factual answers eg. biology.
Though the tutors are available for some support, I did often feel I was very much on my own. I would say if you're willing to work hard and put in a fair chunk of time, as well as feeling you'll be able to absorb or study information primarily through written materials without a class, then I'd say it's fairly achievable!
Just in case you're curious I did paramedicine, so this consisted of psychology, biology, and health and social care units.
Hope this helps