I nearly gave up on this several times, but glad I persevered.
Looking at the same word as Lumen (I think) - The extra letter in 12 would need to be an E, but from the wordplay it looks like a D?
Ah! Thanks, Quisling. I had the letters from 9 to 12, which i convinced myself fitted "intersecting circles"
I wonder if there is term for this type of puzzle.
Loved this. It has taken me ages but I finally got there apart from 3. ‘ Computer feature onliners frequently used to make money in North America’. I have all but the two non-crossing letters. it begins or end in t , and there is an extra L in the wordplay. Can’t find any word that fits!