Channel 4 has been advertising a documentary program(me) called 'Baby Bible Bashers'. Now, to American ears, this sounds like it could be about miniature Richard Dawkinses or Madalyn Murray O'Hairs, since we're used to hearing the word basher in such contexts as gay basher--i.e. someone who hates and beats up gay people. In BrE, however, Bible basher is the equivalent of AmE Bible banger--i.e.
According to the OED (1989), both Bible basher and Bible banger are originally Australian/New Zealand terms, and the UK equivalent would be Bible pounder, Bible puncher or Bible thumper (the last of these would work in AmE too). I'd expect that this information will be updated significantly in the new edition (though it'll take them a while to get to B, as they started with M), to reflect the spread of the terms (a)round the globe. In the meantime, all of the OED's examples of Bible banger are antipodean.
Banger has other meanings in BrE. It can be a sausage (often in the dish bangers and mash), a small firecracker, or an old and poorly maintained car.