I am lookng for a report which details the outstanding 'picking notes'. Can anyone advise please?

If you need to know what are the orders awaiting Pick list
printing,you may look up the display sales order status or
print the report for the same.

Since both of these have orders with all the statuses, you can use the 'order' option in the tool bar and then filter for status
= 3 or 4 as the case may be in your order types.

A standard baan report can also be customized / simple SQL
query can be written to get the report specific to any order status.