What's your phone signal like / Data allowance. If its good enough, you could use your phone as a backup wan connection using tethering. There is a cheap mikrotik device that will do it for your

How many drives? You can normally pick up cheap 2nd hand nas boxes for next to nothing

Unless you have already, you need to reach out to Vodafone and ask for the details to set up your own router.

I had to do this when I had my fibre connection installed and to setup my own router

When you say your Windows machine is getting an external ip, is it an actual external ip or that it's the 169 address that your machine gets when it can't speak to your dhcp server?

Can you access the Internet or any other services on your Windows machine?