Kill Mollys, not Kusari, since the BAF would hire any volunteers. The UK, has a history on relying on professional forces and conscripts, as opposed to civilian militias (The War of 1812 mostly had Redcoats, although there is the Canadian Militia Myth.). Any, ahem, 'loyalist militias' have a history of being what most of us call 'terrorists'.
Bretonia should follow this formula, if it has anything like this at all, and have BMM tagged workers taking the law into their own hands, murdering civilians that support the Mollys.
If you want to fight the Kusari for Bretonia, the BAF are recruiting. It's their job.
If you wonder why folk financing the Mollys are getting off scot-free... become a UDA-type terrorist, Mollys in reverse.