Got annoyed and created a work around, not sure anyone else will make use of this but here's the VBS I call as the custom browser.
Option Explicit
On Error Resume Next
Dim oShell
Set oShell = WScript.CreateObject("Wscript.Shell")
Dim strBrowser, strBrowserArg, strARG
strARG = WScript.Arguments.Item(0) ' This captures the preview URL passed by Contruct2
strBrowser = Chr(34) & "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" & Chr(34) 'This is the Browser
strBrowserArg = " -proxy-server= " 'This is the Browser Arguments
If strARG = empty Then
MsgBox "Unable to identify URL passed from Contruct2!"
Else
oShell.Run strBrowser & strBrowserArg & strARG,1,True
End If