Each of director Michael Winterbottom’s films seems exhilaratingly or maddeningly like a departure from the last. His new mockumentary, a BBC TV series here condensed into a movie, follows a friendly but antagonistic pair of self-centered comedians on a week-long road trip through England’s Lake District. Steve Coogan and Rob Brydon play pitiless exaggerations of themselves, touring tony restaurants so Coogan can write a Sunday newspaper article. Really it’s so he and Brydon can bore and annoy and enjoy each other, riffing up a willfully meandering comedic jam session whose highlight has to be the dueling Michael Caine impressions. Other impressions vary, as impressions do (accent-wise, Brydon’s Woody Allen seems much more on target than his Al Pacino, weirdly), and the general question of just where the tedious-hilarious threshold lies will be a rich vein of post-viewing debate, but all parties probably will agree it does get crossed.