These toilets are listed on the DCC website as only been open when there is an event on at the park. However, during the three times that I've been here they have been unlocked and no events were taking place. There is a slight possibility that this opening situation is associated with the nearby road works.
I did a quick search on information about the park and could only find a bit about the owner of 18 Emerson St in who 1984 developed a samll part of the adjacent reserve with a lisence to occupy. Later, in 2017 the Property owner applied to the city for revocation of the reserve over this bit of land. One submitter in oposition wished to be heard at the hearing but this failed to prevent the loss of this piece of reserve.
Currently the park has playing fields for soccer and rugby. The given coordinates take you to the eastern side of the building. There is a locked door to the changing rooms in the centre of this mural. To the south side you will see an entrance to the men's toilet and around the corner there is the entrance to the ladies. The building is concrete blocks painted with murals and has a pitched roof.
There is a small stream between the building and the road so keep and eye on any young people with you.
I only entered the ladies. Enter, and turn left. Ahead on the far wall is a solid looking stainless steel hand basin with a soap dispenser above it. There are no hand drying provisions provided. On your left is a green wooden door into the cubicle the stainless steel loo is in the far corner and the cistern is protected inside a stainless steel container. The flush button is on the top. When seated, on the wall to your left is a large toilet roll container holding two of the large toilet paper rolls. There is also a hand rail for those who want to use it. Plenty of room is available to maneovour a wheelchair. The door to the cubicle has a solid bolt latch. There is a chain mesh metal gate to lock the entrance way.
The cache can be found at S45 5A.BCD E170 2E.FGH
A: Number of letters in the surname of the artist, minus (the number of obvious hats been worn by people in that mural x 2).
B: Number of pink flowers on the wall facing the road x 2.
C: Count the number of birds, hearts and dogs in the mural facing the road.
D: Number of cats in the mural facing the given coordinates.
E: Number of V shaped suports to the seats attached to the wall
F: At the nearby set of playground equipment, count the number of rungs on the ladder to the slide and minus the number of animals on the round the round swing seat,
G: Value of the second digit of the number after the name of the artist.
H: Number of grooves on the underside of the slide, minus the value of the first digit after the name of the artist.
Checksum = 22
The cahe is a short walk away. (Less than 10 minutes).