We've had a few projects about gluten free beer at work so I was interested when the IBD magazine had an article on it. It was written by someone from a company that makes a protease normally used to prevent beer from forming chill hazes. By happy coincidence the enzyme breaks down the immunoreactive epitopes in gluten, so it also makes beer safe for coelics.
The author included a list of gluten free beers available in various countries, and listed the grains they're made from.
The lager is slightly oddly made with Amarillo hops, but not a huge amount, and has an unpleasantly harsh tang to the aftertaste. I suspect it's made with sorghum malt extract which could explain the tang. Having paid Borough Market prices for the bottle I made sure I finished it, but it didn't taste great so I won't be getting any more.