Clean install Mac Pro 2010

I have a mid-2010 Mac Pro that refuses to accept a System installation via Recovery Mode. Each time I try this it simply returns to Recovery Mode. Resetting the PRAM, PMU, all to no avail.

So it looks like I need to do a complete reinstall from scratch. Problem is, I don’t have the Mojave installer on a USB memory stick and the Internet Restore option doesn’t work on this old machine. Worse still, I don’t have access to another computer. Anyone have a possible solution?

Many thanks!