I have just started my self study of SBL using Kaplan text book for Sep 2019 exam sitting. However the text book is extremely large and I'm afraid that able to cover the whole syllabus until sep. And for this reason I thought to move to BPP. What do u advise?
I would advise you to use kaplan.
I prefer BPP books, think they are easier to read but I think they are more comprehensive than Kaplan so may be even bigger than what you have. I would recommend the webinars from ACCA study support to listen in the meantime.