@AC re: "authoriser" . That's not the point
The 1990 computer misuse act defines what is illegal as defined by legislation passed by Parliament.
An EULA falls into the category of a License (End User License Agreement), so is contract law rather than criminal law.
License agreements can be (and often are) challenged in the courts, and can be deemed unreasonable. I'm sure that I could if I looked hard enough find a precedent where just what you have described has been judged unreasonable, but you have to be careful of the jurisdiction of the court system looking at the case.
Even if a bad EULA were found reasonable, the penalty for infringing it would be a financial rather than custodial, and may not even be enforceable (for example, if the EULA is judged in Texas which is often where these things are tested, and you are in the UK, then so long as you didn't visit the US, it is unlikely that any action could be taken).
BTW. If you are a Windows user, stop and really read the conditions on the Microsoft EULA that you almost certainly agreed to when you 'accepted' (whatever that means for a pre-installed system) them without checking. I think you will be surprised (and maybe a bit frightened) by what you've signed up for!