Why not? By "major" I mean the Labour, Conservative and Liberal Democrat/Liberal/Alliance/etc leaders.
1945 - Sinclair by default
1950 - Davies by default
1951 - Ditto
1955 - Eden
1959 - Macmillan
1964 - Wilson
1966 - Heath
1970 - Thorpe
February 1974 - Thorpe
October 1974 - Thorpe
1979 - Steel
1983 - Steel
1987 - Steel
1992 - Ashdown (there seems to be a trend here.... )
1997 - Blair
2001 - Blair
2005 - Blair
2010 - Clegg
Wait... Harold Wilson and Ted Heath were better looking than Jo Grimond? Bullsh**t
Other than that, list seems about right. Although I think David Owen was more classically handsome than David Steel for 1987, but they were both pretty telegenic.
Charles Kennedy was not a bad looking man either, especially when he was younger, but as he's aged, I've noticed recently that he looks more and more like he's sucking on a sour lemon. I suppose realizing that your party is going to be decimated in the next election will do that to you.