The i-Finance Payment run BACS files should be read only!
This is important for security, as someone could change the bank information on the file before being uploaded to the bank/BACS provider.
The only indication this has happened is when a supplier chases for payment.
The work around is to download the BACS file (used to pay suppliers) and the i-Finance BACS file and compare the two, to ensure no changes. This doesn't add any value, time consuming and is pointless.
There is no need for the i-finance BACS payment file to be editable. As overrides all the checks made up to that point.