I am not sure the Supreme Court Pimlico Judgment takes the law much further, although it remains to be seen how Tribunals read it. But it probably does tell you which way the wind is blowing. If I were an employer I would be very careful about assuming someone is not a worker as Tribunals and courts are increasingly  leaning towards giving individuals the rights of a worker. Hopefully the government will give some clarity soon, although given the issues with Brexit I am not holding my breath.