Table:
0
A
B
C
D
E
F
G
1
DVD Title
No. of Discs
Year
No. of Episodes
Region 1
Region 2
Region 4
2
Series 1
4
1978
13
14 May 2002
N/A
2 January 2013
3
Series 1, Volume 1
3
1978
6
N/A
7 April 2003
1 September 2003
4
Series 1, Volume 2
3
1978
7
N/A
5 May 2003
1 September 2003
5
Series 1 & 2
8
1978
27
N/A
N/A
5 October 2010
6
Series 2
4
1978
14
15 October 2002
N/A
2 January 2013
7
Series 2, Volume 1
3
1978
7
N/A
7 July 2003
5 May 2005
8
Series 2, Volume 2
3
1978
7
N/A
15 September 2003
5 May 2005
9
Series 3
4
1979–1980
14
16 September 2003
23 October 2006
4 May 2006
10
Series 4
3
1988
10
14 September 2004
26 December 2006
11 April 2007
11
Series 5
4
1988
12
19 July 2005
3 March 2008
2 April 2008
12
Series 6
4
1989
12
25 July 2006
18 August 2008
2 April 2009
13
Series 7
4
1990
13
14 August 2007
26 December 2008
18 May 2010
14
Christmas Specials
2
1983 and 1985
2
16 September 2003
20 October 2008
2 April 2008

Questions and formulas:
Question: What is the largest number of episodes for a 1989 season dvd release? 
Formula: MAX(FILTER(D1, C1=1989))
Formula2: MAX(FILTER(D2:D14, C2:C14=1989))
Level: easy
Question: How many  dvd  titled "series 5" were released having a release date or a non available date in region 2?
Formula: ROWS(UNIQUE(FILTER(F1, A1="Series 5")))
Formula2: ROWS(UNIQUE(FILTER(F2:F14, A2:A14="Series 5")))
Level: medium