I would be surprised if they are self-employed - and if they were, they and, in this case, Saracens would be at a future risk from the next tax year when IR35 is supposed to be tightened-up. To be slightly frivolous, to be self-employed they would have to supply their own kit, decide for themselves how they deliver their services and invoice Saracens after each match or whatever. All their work is controlled by Saracens (and that applies to Wasps and other clubs too) so that sounds like an employment contract. I am a consultant to a number of clients, decide for myself how and when I work for them, have my own office, pc etc,and then deliver services to them. Doesn't sound anywhere close to being an employee. And I certainly don't want my client deducting tax and NI from my fees. That's my responsibility.