One of Britain's grubbier little secrets is out of the closet. Clothes moths appear to be making an annoyingly widespread return - their numbers swollen by the insects' love for our bulging, and not always impeccably laundered, wardrobes.  Reports of infestations have risen sharply in the past six months. Some have attributed this to the demise of the traditional mothball, others to global warming. But, it seems, the real problem is us and our over-heated bedrooms full of more clothes than ever before, not all of which are as clean as they could be.  The larvae of the common clothes moth, or Tineola bisselliella, can live for up to two years among our clothes - and these days they have an awful lot more to lunch on. Consumer expert Lucy Siegle said research by Cambridge University indicates that the average British woman buys about 62lb (28kg) of clothes each year and has four times as many clothes in her wardrobe as she did in 1980.  an added inducement f