This is worth doing Alan.
As a side note - there was a good extension that provided back end control of K2 attachments, provided a full listing of all attachments and allowed some control over ordering - aptly named 'attachments manager' plugin - it extended K2 V2 & 2.1 but it was not updated to work beyond that. The original author appears to have dropped out of sight.
I've attached the zip below. Don't install it on 2.2 or above, it doesn't work.
Original thread:
community.getk2.org/forum/topics/attachments-manager?commentId=3536014%3AComment%3A13269
It might provide a start point.
Rgds
Mark