The Omnibus featured in this 1907 scene is the same and carrying the same advertisements as in Voyage into Fear (1988) set in 1912. The release dates 17 years apart.
The events in this episode take place in April 1907, according to a caption in the opening titles.
This episode takes place in April and May 1907.
The Omnibus containing the staff readying for their day trip has a shot of Hudson the Butler standing outside - the main adverts on the bus are for Hudson products.
This is certainly the saddest programme of the entire five series. The story is so tragic and heartbreaking.