Please correct me if my layperson's interpretation is wrong, but that IP clause is one of the few things I don't worry about in UK employment contracts. When I first came across the phrase "during the course of employment"[1] that they invariably use and researched it, I got the impression that it seems to have specific legal meaning of when you'd reasonably be considered to be 'working for' the company. At the place of work, on duty for them, using company equipment, etc.

There are much more egregious terms in most copy-paste contracts that you can helpfully point out to HR people if you're feeling helpful (or mean), including attempted rewrites of UK labour law (meaningless, it always takes precedence) or ceding rights, to more subtle things such as full-time jobs disguised as freelance contracts, putting you at risk if the taxman comes a-calling[3].

[1]: https://en.wikipedia.org/wiki/Course_of_employment [2]: It's mostly used to judge whether the employer is vicariously responsible for an employee's offences, e.g. was the delivery driver on his own time or was he in the course of employment when he hit the pedestrian? [3]: https://en.wikipedia.org/wiki/IR35