The DA42Ms are on the mil register also as ZA179 and ZA180. I'd guess they are for Iraq. Possibly to free up some of the Defenders for Afghanistan.
Some pics of them here:
UK Airshow Review - iB::Topic::When Serials Surprise... Pics obviously taken pre-conversion to the spec described in the RUSI article.
I reckon they'd be pretty useful in ISTAR role. You could have line of sight video transmission to guys on ground, and also via satellite uplink back to ops. Dirt cheap too (militarily speaking) - you could buy dozens of them and give every ground patrol permanent overhead video cover.