"at the crease"

He's working on ideas.

An umpire is the same as a referee. Sundry means various. I don't have enough context to know, but it appears that the author is extending the metaphor of "at the crease" by saying various referees--extending the sporting metaphor.

"That's enough!" He said.

The metaphor is now clear:It means the individual in question is still "making the running" despite attempts by various dissenters (shouting "owzat ?" to sundry umpires) that he should no longer have the power. (be given "out" in cricket)

I got it, thanks a lot! Fresco

I was quite helpful too, if I might modestly claim so to have been.

of course you are helpful, thank you very much, Mc Tag!