Hi, the algorithm checks every song to decide if or not they are classical or not, then if there are more songs marked as classical than not classical the release is marked as classical, or vice versa.
In this case of the 17 tracks 7 were marked as Classical and 10 were marked as Not Classical so it was marked as not classical. This is because the majority of the tracks did not have alot distinguishing them as classical
Recording Artist and Track Artist are different this gives a point for classical. But there are no orchestras, conductor or obviously classical instrument credits. Most tracks do not link to a Classical work type, and do not use common classical terms in the song titles.
You are correct to say some of the composers are not in the composer list, but maybe the easiest solution is to add Craig Ogden to the Classical People list, this worked for me.

Also, I note the release is on the Chandos record label, and this is a Classical only record label. I do have a short list of Classical releases and it was missing from this list but if I add to the list this also marks the release as Classical. However, this list currently only exists in the code therefore only i can do this, so I have create an issue to move the list to an editable file https://jthink.atlassian.net/browse/SONGKONG-3057