Which level to study

Hi , I'm in my 40s now and have an interest in doing maths again.
Question is , I've got the gcp foundation book and have been working my way through but I'm wondering do I complete this book before going to the higher book or can I just jump straight into the higher level and learn straight from there?
Basically I'm hoping to get a good grade this time but not sure if the higher covers all the foundation in one go.

Tia 😊

Higher textbooks will include everything you need to know for the higher exam, including the foundation topics.

But the foundation textbook will include some of the basics that you won’t find in a higher textbook - the higher book will assume some knowledge.