I don’t know if it’s the diet or something in their water supply, but Iceland seems incapable of creating bad films. And with Benedikt Erlingsson’s latest, after the wonderful Of Horses And Men, we may just have the finest film to come out of the island; one that is deftly timed, hugely relevant and, above all else, hugely entertaining. Woman At War follows the daily routine and double-life of Halla, a 50 year-old who is a choir master by day, and a dare-devil, militant environmental activist by night, waging a near one-woman war with Iceland’s aluminium industry, which she deems…