Billy has now won 8 games in a row 6-0 and now 2-0 final set. Think I may have answered my question above perhaps.
I haven't really been watching much but from small the bits I've seen, there's been no MTOs, Gray doesn't have any strapping or anything, and he seems to be moving fine.
Watched the last 15 mins - couldn't see any issues - Ali G's backhand was a little wayward. And he didn't come into the net much - which may be because he was tired/carrying a niggle but may be because he was pushed back as Billy was playing well up the court, taking the ball on.