Are you using any other protection programs? Have you tried to download using Microsoft Edge?

I just retried starting Windows in safe mode and the download now works. Any idea what sort of programme would be casing the problem? As I said before no issues with Chrome or Edge

It is possible that (anti-virus) security software is causing the problem. Try to disable security software temporarily to see if that makes a difference.

I think I have narrowed it down to a file called printdisp.exe https://www.file.net/process/printdisp.exe.html So far so good. I well leave this thread open for a while to see if the issue returns