I managed to sort it out, so just wanted to mention the solution in
case it helps anyone else out.
The problem was that a couple of the text boxes on the form were not
unbound - their control sources were set to calculations of length of
service as a customer etc. This meant that I was not able to change
their value, resulting in the error described above.
The solution (or at least my solution) was as below
Thanks again for your help
Public Sub ClearForm(frmClearedForm As Form)Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=9887
Dim ctl As Control
'Cycle through the controls
For Each ctl In frmClearedForm
'Test if they are textboxes, listboxes etc
If TypeOf ctl Is TextBox Then
'Check if it's unbound
If ctl.ControlSource = "" Then
ctl = ""
If TypeOf ctl Is ComboBox Or TypeOf ctl Is ListBox ThenReference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=9887
ctl.ListIndex = 0
If TypeOf ctl Is CheckBox Then ctl.Value = False
If TypeOf ctl Is OptionButton Then ctl.Value = False