Dual Boot without access to other drive?

UkChris79 said:

The aim is to have two separate instances of windows 10, that can not see each other, one for the kids to play games, one for the adults to work. obviously I do not want my work one to get a nasty surprise when the kids do something silly.

Just removing the drive letters in disk management should suffice for that. The boot files (EFI System partition) set up for software dual booting can be on one of the SSDs or duplicated on both SSDs and eliminate the need for UEFI firmware switching between boot devices. That does not affect one OS from seeing or not seeing the other OS once it is booted. I would set up software dual booting with the default set to the kids' Windows 10 and a short time delay like 3-5 seconds. Then when you want to boot into your work Windows 10 you know that you have to select it within that timeframe, but if the choice is ignored it goes into the kids' Windows 10.

would encrypting the drives with bitlocker do the trick?

UkChris79 said:

would encrypting the drives with bitlocker do the trick?

Yes, if you have 2 Windows 10 Pro licenses. While you may be able to install 2 instances using the same key according to EULA you need a separate license for each instance installed.

You can set it up like this windows 7 - Separate BitLocker encryption for dual-boot Win 7 8 system--make only one drive accessible at a time - Super User

Alternatively you could just set your kids up as limited accounts and then they will not be able to break anything or (for the price of a Windows Pro license) buy them a cheap second hand laptop...