The tennis court and bowling green for Oldham House Hydro used to be on Cavendish Road, close to the junction with Wellington Street. To the left is another tennis court, presumably also belonging to the hydro. Similar pictures of the courts and green date from during and just after the First World War.

The tennis players are posing for the photo, as they are all facing the camera, and the bowls players are also stationary. Both groups have an audience as spectators are seated around the perimeter, on the rustic seating beside the tennis court and on deck chairs at the far end of the bowling green.

The advertisements below are ones of a series that were placed in newspapers in the 1909 and 1910 seasons, offering both tennis and bowls as pleasurable activities.

The annual garden party of Matlock Bank Methodist Circuit was held in the grounds of Oldham House Hydro in the later 1930s. The entertainment provided included bowls and tennis tournaments, followed by an evening concert in the ballroom. The last of these events took place in the summer of 1939^[1]. The former pleasure grounds are now covered by tarmac as the land has become a council car park.

See samples of their notepaper on Matlock: Letterheads of Local Businesses, 1900-1949 (4), N - R
The Vernon Lamb Archive, Hydros and Convalescing, Index has 15 photos of the hydro's staff and guests.

References:

^[1] "Derby Daily Telegraph", 23 June 1939.