Solution to battle “during duties” vagueness in IP contract clause in UK?

Side projects for developers and who owns the IP and copy rights to works created outside of the "course of your duties".

How "course of your duties" is often(and possibly incorrectly) interpreted:

As the employee: During working/contracted hours as a permanent employee, using company resource. As the employer: While you are employed by the company 24/7. i.e everything you code belongs to us while you are employed here.

I cam across some advice that seems really interesting:

"open a company and hold the IP rights, trade marks and project in the name of that company. You can be the sole Director and own it 100% but legally it is a separate entity from you or them."

So essentially you would be working two jobs and have signed two contracts.

Who now owns the IP and copy rights for the code you create?

Baring in mind this would be for side projects NOT competing in the same space you current employer is in. If you work for a company that is into everything - that's a separate conversation.

Personally I think this is dangerous thinking. Technically, you as the individual would still be the creator of said code assets and would potentially have broken the law by handing over said assets to another company. But the problem here is: If there is no clause saying you can't have a second job. Does the code you develop under the working hours of your newly founded company's contracted hours(weekends) really still belong to your "first employer" due to the "during your duties" where contracted hours are (weekdays - 9am - 5:30pm) part of the IP clause?

How do you handle clauses like this when you work two jobs or freelance for example on weekends - both legally and discreetly?

Aside from leaving of course.