Disable Macro if Read Only

I've tried searching for a solution to this, but as yet not one found.

Is there a way to disable the below macros if the file is opened in read only? i.e. only run them when the file is opened as write and read?

Here's the code I'm using at the minute:


Module 1

Dim DownTime As Date

Sub SetTime()
DownTime = Now + TimeValue("00:05:00") 'change time as needed
Application.OnTime DownTime, "ShutDown"
End Sub

Sub ShutDown()
ThisWorkbook.Save
ThisWorkbook.Close
End Sub

Sub Disable()
On Error Resume Next
Application.OnTime EarliestTime:=DownTime, Procedure:="ShutDown", Schedule:=False
End Sub


ThisWorkbook

Private Sub Workbook_Open()
MsgBox " Welcome to Master Sales" & vbCrLf & _
" This workbook will auto-close after 5 minutes of inactivity"
Call SetTime
End Sub

Private Sub Workbook_BeforeClose(Cancel As Boolean)
Call Disable
End Sub

Private Sub Workbook_SheetCalculate(ByVal Sh As Object)
Call Disable
Call SetTime
End Sub

Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Excel.Range)
Call Disable
Call SetTime
End Sub

Thanks in advance!

Magic, thanks!