Well there is definitely something going on with usb hdd and 5.0.013.
I flashed back to 5.0.011 and my osmini could see my drive again and looking in /dev I could see sda and sda1.
As 5.0.013 is now available in the image manager I used that to flash 5.0.013 and I once again lost my usb HDD.
With 5.0.013 my osmini could see my 8GB fat32 pendrive but could not see my Seagate 3TB usb HDD ext drive.
I've attached the dmesg file from both 5.0.011 and 5.0.013.
Looks like I'll be staying on 5.0.011 for the time being.