I was looking at band 6 geography responses and with medium handwriting its about 7-10 pages for a 19-20/20 whereas for small handwriting it was around 4-6 pages for a 19-20/20.
Advanced English: Low 80's
Business: Low 80's
Chemistry: Low 70's
Biology: Low 80's
Keep in mind because exam difficulty changes for year to year these are very hard to precisely estimate.