I will be receiving a new Windows 10 Dell laptop tomorrow, that I will be using for work. We are a small company, and don't have a central IT function. I would like to secure the laptop such that no-one can access its contents if I lose it, or it's stolen. I'm thinking of whole disk encryption or similar - what is the simplest way of going about this?
Windows 10 Home has Full Disk Encryption built in. This is more than enough to protect your data from theft. If you’re worried about the NSA, you may want to use a different encryption solution like VeraCrypt.
Win10 professional also has BitLocker built in, a more powerful encryption solution than de Home version default. But this sends your recovery keys to the microsoft server. Very convenient but maybe less private.
I'd suggest VeraCrypt's full disk encryption.
Check out their Wiki for more information. Please make sure you create a rescue disk and store that somewhere secure in a safe.