I am taking an OU course instead of an Access course. It is a perfectly good route into university but you will need to do a lot of research. I am doing 120 credits at level 1 with the OU so I can apply to UCL in October but before I began I made sure what course/level my preferred university required. What course have you already completed? I’m not sure if doing an OU law course is a good idea, the best universities might prefer you to take humanities or social science subjects.
You should email every university you are interested in and ask whether an OU course would be acceptable for admission onto their Law programme, how many credits they require (and at which level), and what subjects they prefer (humanities, social sciences, law, a language etc). If you like a university which says yes then do the OU course, if not, find another route.