I used these for my panel : Buy Cable Markers HellermannTyton Assorted Clip On Clip On Cable Marker, Pre-printed with 0 to 9, Pack of 200, HellermannTyton 561-05030 online from RS for next day delivery.
Not as cost effective if you want loads of them, but it cost less than a tenner to do my panel.

BTW Ed, your machine is looking great. I still can't believe you managed to cram all your electronics in that enclosure! I'm using one the same size and gave up trying to get the VFD inside as well as everything else.

Si.