'Rennies' are a brand of antacid tablets.
'Gay Gordons' and 'Valeta' are types of social dances. Gay Gordons is a lively country dance popular at Scottish cèilidhs, and the Valeta is a waltz with graceful gliding side-steps.
Trixie tells Jenny that they will be like Pinky and Perky (1957). Pinky and Perky is a children's television series first broadcast by BBC TV in 1957 and revived in 2008 as a computer-animated adaptation. In the TV show, they are anthropomorphic puppet pigs.