Having read up on that add last and d, I must agree.
Not having used it as I said, it was this that misled me
When I did the bcdedit and bcdboot commands on my Windows 10 (bcdboot E:\Windows /d /addlast didn't seem to register in cmd), I wasn't able to boot to Win 10 anymore as it keeps booting into Win 7, even when I chose to boot from Win 10 drive.
Whilst I will stay with the cmds I usually use, as I have never had a problem with them, when starting from a clean bcd, I must agree that if the cmds have been entered correctly - spacing it etc., it should, most certainly have worked, so there must as you say have been some other problem, with the way the dual boot was configured before the thread started.