Hey, does anyone know what the approximate cut-offs for a Band 5 or 6 is this year for advanced English based on other years?
No, it's imposible to tell - and even if we knew what the cut-offs were going to be, they wouldn't be of any use to anyone, because you can't know your raw mark for the examination paper until you've actually completed it.
The raw examination marks are completely different to your school marks.
Would the BOS decrease the band cut-offs as it's the first year for the New Syllabus in English?
The cut-offs are always determined so that a band 6 performance in the particular year is equivalent to a band 6 performance in previous years (and likewise for the other bands).
They aren't increased or decreased for other reasons.