This episode takes place in 1959.
Spike refers to Brenda driving "one of those new Mini cars which have just come out". The Mini was launched in August 1959 and was known at the time as the Morris Mini-Minor. It remains in production (under its self-titled marque) as of 2021.
It is stated during this episode that both Mr. Partridge and Spike both have the day off on Saturday, But Mr. Partridge is forced to turn up to welcome the new campers in full costume, and Spike is allowed to go to Edgbaston to see his girlfriend, even though Joe Maplins Telegram states that he wants 'The Camp Comic larking about and acting the goat' so the reason for spike' being allowed to have the day off is never explained in the episode.