THE FEDERATION of Entertainment Unions (FEU, of which the NUJ is a part), offers free training for freelances on "the business side." Upcoming FEU Training courses include Negotiation for Freelances on 12 July in London: see www.feutraining.org/2018/negotiation-for-freelances-12-july-london
NUJ professional training courses in London resume in the autumn with Winning and Negotiating Freelance Work. It's on Friday 21 September in London. It costs £70 for NUJ members, with a discount for student members, see www.nuj.org.uk/events/2018/09/21
The Data Journalism course has been postponed until the autumn.