I’d check that this degree would qualify you to be a child psychologist - it doesn’t look like it would, from first glance.
From a uni careers service:
An industry-approved doctoral degree is usually required to become a Child Psychologist. This must be in a relevant subject – such as psychology, nursing, social work, or sociology. You’ll also need to have at least two years’ (voluntary or professional) experience working with children or families to get started.
This doesn’t appear to have any industry backing and no longer qualifies for teacher training either, so you might find that it’s not very useful in terms of next steps and you need an additional degree or other future learning to get there. It’s worth checking 
I did a few law modules with the OU but half way through, they were reclassified and didn’t count as a qualifying law degree anymore; so I had to change to a different university and repeat the modules.
I will say that although I thought I’d love the OU and being able to do it from home around other commitments was a dream come true, I did love going to actual uni, and it was a totally different experience. We had a lot of random but useful conversations, lots more reading and learning, and it was nice to really “know” people who were studying. The OU was quite different; they didn’t encourage reading anything additional to the books they provided and the lectures and homework was very linear.