I have an HP laptop running Win10 Home. The OS passoword has been lost and I need to repurpose the laptop until such a time the password is found (I think I have it written down at work, but work is closed due to the virus...).I do not want to erase the password with some hack as there is data on the drive belonging to a third party and I want him to be  given access to it so he can see it has not been read by others.  Can I remove the HD and clone it on to  a full size external drive and then wipe it, without having the OS password (the BIOS is not passworded)? I can then put the laptop back to use without buying a new small drive for it. Thanks.I am guessing there's no way to clone the drive in the laptop WITHOUT physically removing it?

So this is just a simple OS password?  There's no actual encryption solution like BitLocker involved?  If so, then this is going to be a completely standard case, and there's no need to remove the laptop drive.  Just boot the system into Rescue Media and choose to clone the disk to wherever you want.  Or actually, given your situation I would recommend making an image backup of the drive and storing that on another drive instead of cloning to another drive.  An image backup will store the entire disk image as a single file on the target, which means that data can coexist with any other data on the target drive, rather than requiring you to allocate the entire drive to being a clone of your laptop drive.  And once you've got an image backup, if you need to extract any data from that drive image, you can simply mount it on any PC that has Reflect installed and browse it just as if it were an external drive.  And later on, you would be able to restore the image of that drive back to your laptop if desired.  And actually, if you have a Pro version of Windows 8 or newer, with an image file you'd be able to use Macrium viBoot to boot your disk image as a virtual machine, and from there you could use any "hack" tools to reset OS passwords that you wanted in order to try to get into your laptop's actual Windows environment if you wanted/needed to do so.  If you succeeded, you'd be able to use your laptop's Windows environment right there in the virtual machine.  Any changes made within viBoot are stored separate from the original image file, so all of that activity would be completely non-destructive to the original data that was captured from your laptop.

There appears to be no rescue disk with it, is it too late to create one that will boot into the drive? I am also thinking boot into a Linux Live distro and access from there, but an image file sounds by far the best option, many thanks for your in depth reply, much appreciated!

Try creating Rescue Media from any other PC that has Reflect installed.  When dealing with typical laptops and desktops, Rescue Media created on one PC will quite often work just fine on another PC.  It's not a guarantee, which is why it's preferable to make Rescue Media on the PC you actually plan to use it with, but it tends to work.  I'd recommend doing it from a Windows 10 system, or else if you need to do it from a system running an older version, in Rescue Media Builder, click Advanced > Choose Base WIM and select WinPE 10.  That will give you the Windows kernel with the most expansive hardware support built in, and therefore the greatest chance of success.

If the Rescue Media can't see your internal disk, then that may still be fixable, but it would involve adding drivers appropriate to your system into your Rescue Media.  That's doable, but try what I've just described first, because there's a very good chance that it'll work fine.  Good luck!