Yes the default of 110 applies. 18000 is 5 hours if my math is correct which is a little long but then it looks like you've bumped the maxRequestLength up to close to a gigabyte. If you've got files that big then 18000 could be a decent time. Basically you want to set those values a low as you safely can as they do affect the website performance. I can't remember exactly what's affected but that's what I was told back I was asking the same questions on the old ASP.NET forum.

Further info: the same behaviour happens when I use File Manager to upload to the site. FTP is fine with any sized files tested thus far. Any ideas please? I really need to be able to upload 20-40Mb files to the repository.

I actually found the answer a few minutes after posting this.  I had copied the setting from the first page.  I then read the microsoft page referenced in the first post and realized that the requestLengthDiskThreshold probably should not be set so high.  Using these settings, I was able to upload a 50MB file with no issues.

<httpRuntime useFullyQualifiedRedirectUrl="true" executionTimeout="1000" maxRequestLength="50192" requestLengthDiskThreshold="8192" />