I didn´t find much info on the Letchworth Scale Model Club about the event, but they might have more info somewhere on their page.
I did find some more info at the Letchworth Event page.
Letchworth Scale Model Club Showcase 2015, Sunday 18 Oct 2015
Discover art and history in miniature. Visit the local event of the year for Modellers, Gamers, and Collectors. Enjoy club displays, painting demonstrations, modelling, war games, trade stands, competitions, and a raffle/tombola!
Open from 10am until 4pm.
Adults £3, Seniors and Children under 15 £1
And if you don´t have the possibility to go there here are some more pictures from Salute taken by Sidney Roundwood, as all Stockholm 1392 pictures in this blog post, please also have a look at his most exellent blog Roundwood´s World.