Xcode 10.1 cannot be downloaded on MacBook Air despite 42GB of space

Title is fairly self-explanatory - I'm running Mojave (10.14.2) on an early MacBook Air 2014. Had uninstalled Xcode before but subsequently re-downloaded the dev tools for some personal programming.

I am aware that I need several times more space than the actual download (Xcode 10.1, 6.1 GB) for the installer and scratch space for the OS to operate smoothly. I am not very sympathetic to that response when I have ~43.28 GB of free space, which I found via 'About This Mac > Storage'. That puts me at around 7x more space than the actual install, which should be more than plenty. Even the most generous estimates I've seen suggest 30 GB is sufficient. Yet I still get 'There is not enough disk space available to install the product.' when attempting to download via the App Store. It's worth noting that downloading anything else is stress-free. So I have no idea what Xcode is complaining about.

I have tried downloading directly from developer.apple.com/downloads, but Safari appears to stop downloading about half way through. Doesn't say it's paused, just appears there's no connection. I admittedly have poor internet, but that strikes me as odd seeing as I can log onto the pages myself well enough. It also doesn't explain why the App Store complains about insufficient storage, which is a totally different issue than a poor connection.

Any assistance would be greatly appreciated - bar suggestions to clear space. I really doubt it would be that by now!