Open an account on the UKCAA portal and register for exams. When registering a training organization, select EAT (Exempt Approved Training) Then send them copies of your logbook, endorsements, current licenses etc, via email. Once they’ve approved you for EAT, you can then book exams.
I’ve studied this stuff before so some of it I am familiar with. So I purely do the questions on ATPLQ, when I don’t understand something, I use the explanations and I also signed up for the BGS webinars, to watch them and try get my head around it.
It’s done the trick so far. The exams aren’t rocket science but it’s more the time consuming aspect that can get frustrating.
Good luck!