You think Eddie Izzard, really? Doctor Who, maybe. The Saint, no way...
I'm not saying he'd be my top choice, just that he'd be an interesting one. Moreso than Scott, I think. I also think Izzard's got more range than we've really seen, and could probably pull it off. (His turn as Charlie Chaplin in The Cat's Meow was probably his Saintliest to date.) But his history with remakes of classic Sixties series is not good: remember The Avengers?
As long as we're discussing comedians, why hasn't anyone brought up Steve Coogan yet? He's British, in his forties, done film and television, not blond, and well-known on both sides of the Atlantic. I don't know if he golfs, though. But he's long shown an (obsessive?) appreciation for Roger Moore both in his characters and out, and he was attached to be Brett Sinclair in The Persuaders! movie opposite Ben Stiller for a while. (Maybe still?) I don't really picture him as Simon Templar, but I do respect his talent so I'm sure he could pull it off...
For the record, my own top choices are both long out of the running: Purefoy and Northam.
Brisco