If you would like to make it easier, here are the names of all the theatres featured but in alphabetical order. If you just want the answers, scroll further down.
Adelphi
Aldwych
Almeida
Bridge
Gillian Lynne
Globe
Hampstead
Harold Pinter
Her Majesty’s
Lyceum
National Theatre
Novello
Old Vic
Prince of Wales
Royal Court
Sadlers Wells
Shaftesbury
Theatre Royal, Haymarket
Victoria Palace
Wyndhams
A. Old Vic
B. Sadlers Wells
C. Aldwych
D. Victoria Palace
E. Novello
F. Adelphi
G. Hampstead
H. Prince of Wales
I. Lyceum
J. Shaftesbury
K. Bridge
L. Harold Pinter
M. Gillian Lynne
N. Globe
O. Wyndhams
P. National Theatre
Q. Royal Court
R. Her Majesty’s
S. Almeida
T. Theatre Royal, Haymarket