Batch numbers
In Sales Return Notes, only one batch number is allowed for each line.
If you are using existing invoice or order lines you cannot change the batch number details, only the quantity associated with the batch.
Multiple Batches
Where multiple batches were shipped against an invoice or order, a return note line is required for each batch.
The and options generate a return note line for each batch/quantity. You can then delete lines for batches that are not being returned. You can also reduce the quantity on the lines.