You want best seats we have them (sic)

I spotted a skinny shop threshold in front of 45 Aldwych;

The thin strip abuts an unbranded basement lightwell and, when this was a ticket shop, it was possibly against a step or counter that ran along the whole frontage. 

This mosaic ghostsign for Keith Prowse tickets, perfectly sited for the adjacent theatres, looks to be mid-1920s to me, although I think a bit of punctuation between 'seats' and 'we' wouldn't have gone amiss!

I had, until now, assumed that KP was a one man concern, but no – the company was founded in 1830 by two musical instrument makers, namely Mr Keith, who had also been selling tickets for events via a messenger service, and Mr Prowse, the comma between their names, as shown in this 1939 directory listing, having since disappeared (as per the mosaic!). 

The directory shows the company merely as musical instrument makers even though they had been selling tickets and publishing music for decades by this time. It's also worth noting the variety of different shops along this stretch of Aldwych at that time, including a chemist, an optician, some solicitors, a picture framer and another ticket agency. Today, the Waldorf Hotel has engulfed most of these small shops.

Back in the early1980s, Keith Prowse was London's premiere ticket agency. I often used their prominent shop at the junction of Monmouth Street and Shaftesbury Avenue, at that time opposite Grodzisnki's the baker, at the end of Neal Street. Ah happy days. There's a bakery there today but you won't be able to buy a pasty, a lardy cake or a belgian bun. When I moved to a new job near Hatton Garden, I was pleased to find another Grod's outlet on Leather Lane.