This sentence is from The Economist 3 Sept 2011. Mrs Dorries, who calls herself “pro-choice” but has form in campaigns to whittle down abortion rights, argues that such charities cannot give independent advice because their financial interest lies in doing more abortions. The WR dictionary has a definition "form in (or chiefly Brit. on) form playing or performing well" but I'm not sure if this phrase collocates with have or if it's even the right definition here. What does it mean to say that the lady "has form in" certain socio-political campaigns? Thank you.