It turns out that even if you delete devices from your network but they are still loaded into your DEP then they are still technically in Meraki so will show in any settings profiles they were scoped to before they were deleted.
Once you remove them from your DEP (only do this if you are disposing obviously) they they disapear from Meraki. The other alternative is remove any tagging from devices before you delete them.
To me this just seems like bad programming but what can you do.