That's the sad thing. Grime is/was the counter-culture, but the top artists are desperate to enter the mainstream. (See: post-BRITs backlash last year)
Sheeran has lots of links to the grime scene, going back to SB.TV.
Don't think he has credibility issues, tbh.
(I bought Boy in the Corner in 2003, btw.)
PS Skepta has been milking Shutdown for waaaaaaaaaaaaay too long now.
The BRITs are mainstream awards. Always have been, and always will be.
PS You forgot Ed Sheeran who, like Adele, probably sold more records than every grime artist put together.