The cliched and indeed meteoric rise of Alt-J has at times dazzled with its intrigue. Having spent years tucked away in student bedrooms, perfecting a necessarily minimalist style yet reticent to unveil it, the Leeds act equally seemed uninspired by the fame that eventually came their way. The wonderfully portentous Mac-only reference of their name, early refusal to feature their own faces in promo shots and distinctive vocals made it clear they were going to do things on their own terms. Terms, in a leftfield twist, that didn’t turn out to include bassist and founder Gwil Sainsbury. It’s been an…