The notional grade boundaries (which are per paper) are harder to screenshot (because of all the papers, and because they intermingle the Foundation Tier and Higher Tier boundaries). So I just provide the link to the PDF, which is here. The Combined Science boundaries start on page 9. Glancing down the list, for a 6-6 you'd have needed between 29 and 32 on each paper which, when multiplied by the six papers, gets you to the 183 overall mentioned above.
Note that the boundaries move about each year, so the above may not be reflective of what the boundaries will be this year.