a quickie note.
I'll try to catch my sister before she leaves the country and get a more definitive answer on Royal Decree. (Historian who can quote you chapter and verse about the British since Hadrian built his wall) 
However, you've already given the answer. No need to recind a decree or writ. The Helsing were acting outside their authority by attacking the crown and killing loyal defenders. 
As in the example i gave on William Kidd. he had a letter of marque to attack spanish ships as a privateer, they hung him as a pirate because one of the ships he attacked (allegedly) wasn't spanish. Helsing had a 'letter of marque' to do X, but they hung her for doing Y. ^_*

__________________________________________________________________
The NEW Netscape 7.0 browser is now available. Upgrade now! http://channels.netscape.com/ns/browsers/download.jsp 

Get your own FREE, personal Netscape Mail account today at http://webmail.netscape.com/

             .---Anime/Manga Fanfiction Mailing List----.
             | Administrators - ffml-admins@anifics.com |
             | Unsubscribing - ffml-request@anifics.com |
             |     Put 'unsubscribe' in the subject     |
             `---- http://ffml.anifics.com/faq.txt -----'