Hello, Thank you for your help, but I have thankfully managed to resolve the problem. I switched my PC internet from wireless to wired and that did the job. I presume the issue was actually related to packets.
Before contacting your Internet Service Provider, the only step I would recommend would be to try a different computer. All of your current troubleshooting has been tested on the same computer. If another computer can complete the download and install process without encountering Error 113, the error would be specific to a computer and not the network.