Hold on that's odd - Dr Who and Million Pound Drop related

The Mail amongst many news outlets reports an odd question and answer on Channel 4's Million Pound Drop quiz:

'A couple who lost a £325,000 TV quiz show prize after the programme's fact checkers got their answer wrong have been handed a reprieve by Channel 4.

Husband and wife Johnny and Dee will return to Million Pound Drop on Friday night and will have their £325,000 kitty reinstated.

The couple were originally booted off the show last Friday night when they supposedly gave the wrong answer to the question 'Who played Dr Who for the longest time?'.

The pair were asked to chose between four actors: Sylvester McCoy, Paul McGann, Christopher Eccleston or David Tennant.

Unable to decide on the correct answer, they split their remaining £650,000 between McCoy and McGann, only for the host to inform them the answer was Tennant.

However, the error led to Doctor Who fans calling in to complain at the factual inaccuracy.

Tennant, the tenth Doctor, played the role from 2005 until 2009.

And while McCoy only played the role from 1987 until 1989, he also starred in a 1996 film and, given that no one else portrayed the Timelord between those two points, he takes the title as longest reigning Doctor.

A statement from Channel 4 read: 'Having spoken to the Dr Who production team at the BBC, the Million Pound Drop producers have confirmed that the correct answer to this question was Sylvester McCoy and not David Tennant as shown on the broadcast on Friday 5th November.

'This is due to Sylvester McCoy’s final appearance in a 1996 TV movie.

'We apologise for this oversight and as a result, the contestants, Johnny and Dee, will return to the show to finish the game this Friday or Saturday at 10pm on Channel 4 with the £325,000 they placed on McCoy.”'

I see something else that's a bit odd with that question; what about Tom Baker?
I calculate that Tom Baker served seven years as the Fourth Doctor to the five years served by David Tennant as the Tenth Doctor. However the contestants were indeed correct Sylvester McCoy was the Seventh Doctor from 1987 to the start of the 1996 film.

Actually a further thought strikes me, the First Doctor appeared in the 1983 special 'The Five Doctors' so from first appearance to last that is 20 years BUT William Hartnell who originally played the first Doctor was dead by 1983 so his part was played by Richard Hurndall. So maybe Patrick Troughton (the Second Doctor) holds the title for 1966-1969 + 1983 (the Five Doctors again) making 17 years?

That's the trouble with quiz shows just looking at Wikipedia, they miss the wrinkles...