FWIW, I'd write your code more like this:
Code:
Sub button_click1()
Dim lRow As Long
lRow = ActiveCell.Row
If ActiveSheet Is Sheets("Clipsal Customer") Then
If Not Intersect(ActiveCell, Sheets("Clipsal Customer").Range("A4:Z5000")) Is Nothing Then
With Sheets("Payment Advice")
.Range("B3") = Date
.Range("B4") = Cells(lRow, "a").Value
.Range("B5") = Cells(lRow, "g").Value
.Range("B6") = Cells(lRow, "h").Value
.Range("B7") = Cells(lRow, "i").Value
.Range("B8") = Cells(lRow, "j").Value
.Range("B9") = Cells(lRow, "k").Value
.Select
End With
End If
End If
End Sub