Thank you very much.
I've altered my code so it now reflects this:
Code:
Private Sub cboLocationID_AfterUpdate()
Dim sManagerSource As String
sManagerSource = " SELECT [tblManager].[ManagerID], [tblManager].[Forename] & ' ' & [tblManager].[Surname] " & _
" FROM [tblManager] " & _
" WHERE [LocationID] = " & Me.cboLocationID.Value & " ORDER BY Forename, Surname"
Me.cboManagerID.RowSource = sManagerSource
End Sub
I altered what you gave me slightly and also put in a space between the first double quotes and the statement, i.e. " WHERE" - has done the trick.