Hi Nic. I'm Greg, an installation specialist and 8 year Windows MVP, here to help you.
There are tips here for managing smaller drives including 32gb drives:
https://www.theguardian.com/technology/askjack/...
https://www.pcworld.com/article/3040404/windows...
https://www.groovypost.com/howto/maximize-stora...
This should make enough space to install Windows Updates. But for now I'd focus on the Spring Creators Version 1803 since successfully installing it when released in the next few days will bring along all Windows Updates and also resolves almost all other problems since it reinstalls Windows keeping your files and programs in place.
Track release of Version 1803 here: https://blogs.windows.com/windowsexperience/#ut...
Once the new version is released install the Media Creation Tool on another PC to create bootable media or download the ISO to stick or disk, transfer it back to the target PC to open the media or click to mount the ISO, right click Setup file to Run as Administrator. This avoids needing the space to download the Upgrade and it's staging files. http://windows.microsoft.com/en-us/windows-10/m...
If the Upgrade Assistant has already been installed by WIndows Update then I'd remove it and it's staging files first to recover that space:
First turn off Windows Update service to regain control:
Type services.msc in Start Search, Open Services applet.
Scroll Down to Windows Update Service and click on it, Stop service and set to Disabled. Now it should clear the queue of Version and other Updates until you turn it back on and Check again.
Uninstall Upgrade Assistant In Settings > Apps & Features.
Clear out any Upgrade folders in C: drive root. Restart PC, try Upgrade again.
Another option is to do the the best possible Clean Install in this link which will stay that way as long as you stick with the tools and methods given, has zero reported problems, and is better than any amount of money could buy: http://answers.microsoft.com/en-us/windows/wiki....
This will give you back all but 15gb of the drive so you can slowly reinstall programs to see how they affect performance, move your files to another drive if possible or offline into OneDrive in the cloud with On-demand access to them only: https://www.pcworld.com/article/3233488/windows....
There is also an automated Fresh Start that reinstalls WIndows while shedding corrupting factory bloatware, saves your files, but doesn't clear the drive to get it cleanest: https://www.howtogeek.com/265054/how-to-easily-...
You can also turn off or block Updates if they are bothering you.
There are ways to block Updates here: https://www.howtogeek.com/223864/how-to-uninsta...
If you want you can set a Metered Connection per the above tutorial, then when ready turn it off to install Updates. You can even wait until the twice-yearly Version Updates to run manually from Media Creation Tool which is a more stable method than Windows Update and includes all previous updates rolled into it. http://windows.microsoft.com/en-us/windows-10/m...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved