System date format and excel calendar input.

[ditto]

In my workbook there are some cells for date entry. I have put excel popup calendars in these cells. But I want the calendar to put the date in the English(UK) format ie. dd/mm/yyyy. But this workbook goes to many places and I want the calendar to put the date in the said format even if the system date format is defined otherwise. Is there a way to change the system date fomat on opening a workbook? Or should I modify the code for the calendar given below?

Option Explicit
Private Const CalendarInputControlName = "CalendarInputControl"
Private Const CalendarInputFrame1Name = "CalendarInputFrame1"
Private Const CalendarInputFrame2Name = "CalendarInputFrame2"
Public Sub HideCalendarInputControl()
    On Error Resume Next
    ActiveSheet.OLEObjects(CalendarInputControlName).Delete
    ActiveSheet.Shapes(CalendarInputFrame1Name).Delete
    ActiveSheet.Shapes(CalendarInputFrame2Name).Delete
End Sub
Public Sub ShowCalendarInputControl( _
       ByVal Cell As Range _
       )
    Dim Calendar As Object
    Dim CalendarFrame As Shape
    Dim CellFrame As Shape
    Dim HorizontalDelta As Double
    Dim VerticalDelta As Double
    HideCalendarInputControl
    If Cell.Left + Cell.Width + 5 + 182.5 > ActiveWindow.VisibleRange.Columns(ActiveWindow.VisibleRange.Columns.Count).Left Then
        HorizontalDelta = -Cell.Width - 10 - 182.5
    End If
    If Cell.Top + Cell.Height + 5 + 123 > ActiveWindow.VisibleRange.Rows(ActiveWindow.VisibleRange.Rows.Count).Top Then
        VerticalDelta = -Cell.Height - 10 - 123
    End If
    Set CellFrame = ActiveSheet.Shapes.AddShape(msoShapeRectangle, Cell.Left, Cell.Top, Cell.Width + 1, Cell.Height + 1)
    CellFrame.Name = CalendarInputFrame1Name
    With CellFrame.OLEFormat.Object.ShapeRange
        .Fill.Visible = msoFalse
        .Line.ForeColor.SchemeColor = 12
        .Line.Weight = 2.5
    End With
    Set CalendarFrame = ActiveSheet.Shapes.AddShape(msoShapeRectangle, Cell.Left + Cell.Width + 5 + HorizontalDelta, Cell.Top + Cell.Height + 5 + VerticalDelta, 182.5, 123)
    CalendarFrame.Name = CalendarInputFrame2Name
    With CalendarFrame.OLEFormat.Object.ShapeRange
        .Fill.Visible = msoFalse
        .Line.ForeColor.SchemeColor = 12
        .Line.Weight = 2.5
    End With
    On Error Resume Next
    Set Calendar = ActiveSheet.OLEObjects.Add(ClassType:="MSCAL.Calendar.7", Left:=Cell.Left + Cell.Width + 7 + HorizontalDelta, Top:=Cell.Top + Cell.Height + 7 + VerticalDelta, Width:=180, Height:=120)
    If Err.Number <> 0 Then
        MsgBox "The Microsoft Calendar Control is not installed on this computer."
        HideCalendarInputControl
        Exit Sub
    End If
    Calendar.Name = CalendarInputControlName
    Calendar.LinkedCell = Cell.Address
    Calendar.Visible = False
    Calendar.Visible = True
End Sub