This list is just all wrong.
No Les Dawson and no Marty Feldman, both of whom are easily in my Top 10. as well as the other omissions people have mentioned. Hancock and Chaplin would be my 1 and 2. French and Saunders each get a place, conveniently equally, when Corbett, Wise etc don't get a place. The great Dave Allen was Irish. Plus I'm not quite sure how or not comedy actors fit in here. Kenneth Williams was very funny even in his own right. Julie Walters is totally brilliant but really as an actor only. Which is to say that she has rarely done stand up or even a sit down, ie reading from somewhat unconventional diaries.