I would not think about doing some ground school along the way I would do it.
You need the ATPL exams under your belt before you can progress forward in your chosen career.
They are hard as well, if you do them full time it should take 6-9 months & part time (distance) anything from 12-36 months depending on how much time you have to commit to it, I think the minimum study time prior to sitting these exams is 650 hours @ a cost of 1800-3000GBP not including accommodation etc.
Best of luck
