In the acquisitions module, when viewing an invoice - and choosing to view this in the Receipt page option, there is a column called Holds.  If any record on this receipt has a hold this number will be displayed.  There is a tiny carrot to allow the user to change the order of this view to see the most holds first.  Unfortunately, Koha displays the holds in a fashion such as 0/1.  The first number is the item levels hold and the second number is the total number of holds on the record (or in this case, the bib level hold).  The sorting will only sort on the first number and if a library only does bib level holds, the sort will never be accurate.