My son has autism and is really particular about his trousers. He likes the softness of jogging bottoms so stiff school trousers are not comfortable. Both M&S and Next have ranges with no front flies or metal hooks which is a start. The material though used for boys has no stretch. He looks longingly at his sister who has grey stretchy jersey material trousers with elasticated waistband which are so much softer. Where can I find similar jersey trousers for boys?