[Britpicking] Help?

I have a favo(u)r to ask of any British English speakers who might happen to see this.

I've submitted my redandthewolf story Seeds of Suspicion to a fanfic archive site, and my (American English speaking) beta there informs me that the phrase to have gotten, in her words, "drives the Brits mad." (I think I once knew that, but then I forgot.)

Anyway, I apparently need help revising this bit to make it British-compliant. Any suggestions?

"It's just," Peter went on, fiddling with his bottle, "maybe there's a reason Remus hasn't been coming over here lately. Maybe he's gotten involved in something that—something that means he can't look us in the eye any more."

The intended meaning is something like he has become involved -- only I imagine I'd want something more colloquial than that for a butterbeer-imbibing Peter to say.

Many thanks!