Think I've cracked it.....I had the Class module definitions completely screwed up. Should be:

Private cName As String
Private cWorkDay(1 To 10000) As Date
Private cJobDay(1 To 10000) As Integer
Private cWorkingDays As Integer


Public Property Get Name() As String
    Name = cName
End Property
Public Property Let Name(Value As String)
    cName = Value
End Property


Public Property Get WorkDay(Index As Long) As Date
    WorkDay = cWorkDay(Index)
End Property
Public Property Let WorkDay(Index As Long, Value As Date)
    cWorkDay(Index) = Value
End Property


Public Property Get JobDay(Index As Long) As Integer
    JobDay = cJobDay(Index)
End Property
Public Property Let JobDay(Index As Long, Value As Integer)
    cJobDay(Index) = Value
End Property

Public Property Get WorkingDays() As String
    WorkingDays = cWorkingDays
End Property
Public Property Let WorkingDays(Value As String)
    cWorkingDays = Value
End Property