DeskPi SBC Shelf 3.5" HDD Mounting

[beatles1]

I got a couple (although so far only one has been delivered) of the GeeekPi / DeskPi RackMate SBC Shelf because they're listed as "(can hard-mount two 2.5” or 3.5” HDDs side by side)" and I wanted to mount 4 3.5" HDDs.

Unfortunately it doesn't appear they actually support 3.5" disks. There are 2.5" mounting holes but nothing matching 3.5". I've bodged it with one screw in one of the SBC holes and one clinging onto the back of the shelf which just about works but it's not ideal. Really you'd want to drill your own holes for this to work properly at which point it might as well be a generic shelf.

Has anyone else used this and am I missing something obvious or should the page be updated to remove the reference to 3.5" disks?