Multisite sub-site gone missing


One of the sites on my multisite network has disappeared.

I have been creating them fine with no problems, and this one actually works when you're in the admin screen, so this works fine:

but when you select 'view site', you get this:

I have a sub-directory in my root hosting, called digital government, so is that somehow 'clashing'? It's an empty directory so that would seem logical..

thanks, Neil.