According to Wikipedia, Diddams is a surname. Notable people with the surname include:
- Harry Diddams (1864–1929), Australian printer and politician
- Nicholas Diddams (c. 1760–1823), English shipbuilder
- Scott Diddams (fl. 2000), American physicist
Who remembers Harry Diddams? He was born in New Zealand. He was a two-time Mayor of Brisbane in 1911 and 1921-1924.

The author of this page has no idea if Diddams Park or Diddams Street are name after Harry Diddams. It just seemed like a reasonable assumption.
From the Posted Coordinates, you can see the playground below. There is no need to enter the playground to answer the following to calculate GZ for the cache final.
S27 41.ABC E153 11.XYZ where # means ' the number of '
(Ignore the green rocker with yellow wings.)
A= (# swings) times (# ships/boats) times (# purple boat masts)
B= # water slides
C= # pirate ships
X= # rope ladders
Y= # blue poles supporting the shade sails.
Z= A minus C
Here is a checker:

Have fun!