I shouldn't have updated my win 10 to latest, Virtualbox is even more messed up now, but at least I'm not alone
Windows 10 Build 10041 - Bridged Network Can't See Ethernet
https://forums.virtualbox.org/viewtopic.php?f=6&t=66682
I've spent so much time messing around with that I've no idea if there are any other new improvments or problems!
forgot to say, on the plus side, I found out that EaseUS who do some good free partitioning software, also do some free backup software which is Win 10 compatable, so you can backup to an image, and then restore using a boot disc.