Park theatre, LondonThe bonhomie curdles as an otherwise unconnected group of women set out to scatter someone's ashes in a promising setup that flounders despite a beautiful set Sarah Rickman's play sets up an enticing, all-female "anti-friendship" endeavour in the wilderness: Mei has died of cancer and her dying wish has instructed her closest friends to come together in the redwood forest of Wales to scatter her a…