HER Girls Aloud bandmates may be climbing Mount Kilimanjaro, but Sarah Harding was tackling nothing more challenging than a mountain of nachos in Manchester yesterday.The Stockport-raised singing star headed to the city’s Hard Rock Café with her boyfriend, DJ Tom Crane, where they were spied tucking into the tasty tortilla chips.Blonde Sarah was resolutely on-trend as she headed to the city centre restaurant in ’80s-style leggings, shirt-dress and shoeboots. Meanwhile her bandmates Cheryl Cole and Kimberley Walsh continued their gruelling ascent of Kilimanjaro on their charity trek to raise thousands of pounds for Comic Relief. I’m sure Sarah was thinking of nothing else as she tucked into a juicy steak, washed down with a Martini…