Dick Van Dyke himself jokes about the accent. He's very good natured about it. I thought he did better, accent wise, as the senior Mr Dawes in the bank.

Robin Hood: Prince of Thieves is a poor film on multiple levels. I generally like Kevin Costner as an actor (and occasionally as a director - Dances with Wolves, for instance), but not in that film. I showed my children The Adventures of Robin Hood with Errol Flynn instead. Still the best Robin Hood ever. :)