Richard, it sounds like you caught the eye of a curator that keeps delving into your stream.. you have some very saleable images IMO, cant see why no sales yet?
If you are quite new to it that could be a reason.. it took me about 4 months to get a sale.. others in a getty uk group i'm in on flickr said much the same.. images are taking forever to get through the review/legal/keywording process and until that happens they wont sell..
I shoot what catches my eye.. but am mindful of logos and potential for releases being needed incase getty do pick up an image.. but I dont get too hooked in the process.. some of my contacts live and breath getty... not good IMO, and couldn't be bothered personally
these are my sales..
http://www.flickr.com/photos/michy66/sets/72157626610663249/
the best seller?.. daft one of my daughter blowing bubble gum, sells most months and 3 times this month!.. the ones from london are very poor IMO, grey day with a P+S but sell to China often!
I sold a rights managed one this month (one of the tower things on the Lowry theatre) I got $283 for that... but on the other hand got $7 for a couple of others.. most seemed to have ranged from $40-80 this month.. not sure i'll do as well every month!