I was in PC World about a month ago looking for inserts, and the ONLY thing resembling them was what you suggested, BUT they were Slim-Line cases, which don't have a tray sheet, and are so thin, the spine is worse than useless. The data on the on-line site seems to confirm this, but I'll go out to one of the two PC World's we've got and see what's what.
I must admit its been quite a while since I've bought any, so I guess the standard stock shops carry may have changed. Hope you find something suitable.
