I have tried deleting the temporary files from path below which is where VS/IIS Express is storing them, but no luck, same errors.
C:\Users\<user>\AppData\Local\Temp\Temporary ASP.NET Files
In terms of .dll's, Newtonsoft.Json had been updated (to v 7.0.1) previously while on Kentico v8.2 and System.Net.Http.Formatting is v18.104.22.168. The web.config has these entries:
<assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-22.214.171.124" newVersion="126.96.36.199" />
<assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-188.8.131.52" newVersion="184.108.40.206" />
At what point is the 'upgrade_82_90.zip' package imported? I have checked the Event Logs via the database and can only see a few events for the site starting but nothing relating to the final steps of the upgrade and I can't get to the 'Sites' application yet in order to manually import the package.