Talk about “alternative” investing. Permira, the British buyout house, is taking control of the family-owned firm behind Dr Martens. A £300-million ($485-million) price tag for punk rock’s favourite bootmaker looks steep. But fashion is an old stomping ground for Permira. It can draw on lessons learned from backing Hugo Boss and Valentino. Moreover, the target boasts a strong brand and a growing global footprint. The only spot of bovver would be if the moneymen hurt DMs’ rebel image.