Practical Grades are the Face 2 Face Skills and Performance - Old School Classic
Performance Grades are Submitted on Line and all about the Performance Only.
My Son was keen on these as he has never really had music lessons in instruments, and didn't take GCSE Music.
Piano, Drums, Guitar and Bass at Grade 6, or it might be 5 is the highest you can start from for some instruments.
I'd like him to do the Theory Grades as his mind sees Music 'Theory' like Maths Puzzles.