TBH I wouldn't bother, I doubt it will get you anywhere.I'll speak with them as soon as I can.
However, I know you struggle with doing a column every month so what about farming it out to 12 "experts" on the DSF. Fairly confident you would get 12 offers of vain people who want to see their name in lights
It would be pretty easy to give each of them a deadline and have one or two articles as a back up in case they let you down (to which they must be named and shamed ) Pretty easy to administrate and ask each author to submit the article details so you don't get repetitive content.