Hi, thanks for the reply.
Right, if I switch back to UEFI in the BIOS, the drive does not appear in the list of bootable media (normally HDD0). If I stick to Legacy Mode (where I have the option to rearrange the boot source order) the option for booting from HDD0 appears, and it moving to first position does not seem to help, as I recieve the "no bootable media" error. In every case I have pulled the USB stick.
I can see that the drive is still physically recognized, it appears listed in the information section of the bios, and I can see it in the SysRescue environment parti