Talking nonsense:
Do you know what I don't understand?
It's a funny idea and well worth making a sketch about but I think you might have a problem here - using Tommy Cooper's death as a "joke".
I'm sure millions of (probably young) people in Britain will be absolutely fine with it but for some of the older people, it might still be a bit too soon.
I guessed with the subject matter I used that I might have some come backs off it, I usually steer clear of stuff like this as well.
I think you'd get away with it if you referred simply to actors/comedians in general rather than to one specific (and much loved) individual.
Even so, you'd be venturing pretty close to Frankie Boyle territory. 