You need to check that the TK school concerned can specifically teach bridging courses - they are separate from the proper ATPL courses.
Unless you can self-certify you need an ATO, so you may as well do a proper course.
The slate notes are good, but not the best for your purposes. Aviation exam would be the best database to use.
I heard on the recruitment grapevine that CATS have stopped taking students, although that may refer to full timers.
You are welcome to PM me if you have any questions.
G