I'm not holding out too much hope here as I'm usually pretty good at digging up obscure and forgotten stuff myself but I've had to admit defeat and call upon Reddit troops!
Given that I watched this sometime between 2013 and 2016, I'm assuming it was released around that time or at least sometime in the 2010s.. it's definitely not earlier than the 2000s.
All I can recall is either a guy on his own or a guy-girl couple travel to a village or small town and stop at some sort of stone outbuilding on some rugged terrain akin to Scottish / Irish / Welsh rural landscape. There's a rather rough and grouchy older fella in the outbuilding. I think maybe the guy/couple stay there overnight and head to the town or village the next day.
They end up at a house where I think they're looking for someone specifically but the occupants of the house are getting ready for some sort of (pagan inspired?) festival or procession. At some point it transpires either one or more of the locals in the house is a werewolf and carnage ensues... My recollection of subsequent events trails off here, which I appreciate isn't helpful!
Definitely British, It's a 'modern day' setting, as opposed to an olde worlde time period.