The Enigma
NPL Magazine
August, 2019
WITZ (adapted)

 The answers to the two clues below differ by only a single letter - which is inserted into the longer, second answer. The first answer has two words.

In London we saw signs galore
Concerning rent and also relief (of a sort);
Sites for lease and sites for release (of a sort),
Some said _ _   _ _ _ and others _ _ _ _ _ _.

Answers:

TO LET
TOILET