If you understand the title, you'll know what connection runs through the answers. If not, the first answer (or a combination of others) might help you get the connection.
As usual (for my quizzes) Please do not put answers in the thread.
I will acknowledge PMs giving answers and posting scores. The full set of answers will be posted in a few days time.
Usual warning: I take liberties with spelling/pronunciation

1 Which musical is based on poems by T S Elliot?
2 Which material was used for making combs, small boxes & frames and inlays, and was predominantly sourced from the hawksbill turtle?
3 What was the name of the fabulous diamond in a series of Peter Sellers movies?
4 How would a native of Tehran have been described (pre 1980)?
5 How might one describe a native of Ellan Vannin?
6 What was the name of the chimp character in the Tarzan films of the 1930s?
7 Who appeared on TV most often with Terry Hall (1926 - 2007)?
8 Which fluid measure is one fifth of a gill?
9 What term describes strike action taken without authorisation by their trade union?
10 What name is shared by an early British home computer, a helicopter, & a body spray?
11 By what name was Mumbai previously known?
12 What word describes a load carrying road motor vehicle with an enclosed cargo area?
13 What slang term is used for an older woman who seeks assignations with young men? (NO! "Stiffler's mom" is not a valid answer to this theme!)
14 What is a mythical creature with, as a minimum, the body of a lion and a human head?
15 What is the nickname of the Argentine rugby team? (a valiant defeat today!)
16 What three creatures were Dorothy, the Scarecrow & the Tin Woodcutter worried they might meet?
17 Which TV character, voiced by Arnold Stang, was apparently based on Phil Silvers as Bilko?
18 What word does not rhyme (although it looks as though it should) with the name of a skin tight garment named for a famous trapeze artist?
19 According to Paddington, what do bears like?
20 What make of car was driven by Inspector Morse?

Mods, please leave in the 'top half' for a couple of days. There are a few music oriented questions in there.

Cheers
Nigel