September 2020
Thanks for all your help so far, sorry this is all taking so long. I'm slightly confused now, when I check for updates it tels me that I'm all up to date, but when I check my OS information it still says I'm running Windows 10 version 1803 (installed in 2018) and when I whcih appeared to have reached end of service in 2018 or 2019.
September 2020
@MaddieTiddy There are Windows updates for each particular build of Windows, and then there are feature updates that take you to the newest build. Among the many reasons for the particular error you're seeing when trying to update, one of them is that you're missing an update to your existing Windows build that your system needs first. But it sounds like that's not the case.
Please do check the Device Manager for updates to the listed components, as described earlier. These are separate from Windows updates, and while Windows will usually download updated drivers for your devices when necessary, it sometimes doesn't work correctly.