Fair enough - I figured he had invested in the company before (to make money, rather than either for fun or purely to take control of it), and looked at the recent move as one to take control of it, but I can see how you'd call the whole event as an attempt to take it over.
It's no coincidence that Sports Direct owned 29.7% of Debenhams. Once a single shareholder (or a concert party of related shareholders) owns 30% or more of any UK public company, they are required to launch a formal takeover bid under the Takeover Code.