You should not attempt the tunnel with kids after or during heavy rain as the tunnel will be much more difficult to traverse. The tunnel was created for lapstone creek to flow through. This cache is only kid friendly when the tunnel is dry. You will probably need a torch and maybe some gumboots, depending on how how soon after rain you attempt this cache, to find clues as you go through the tunnel.
The cache itself is a small sistema with room for small swappables and a log book.
According to a local, this reserve used to be a farm. You can still see the remains of the old convict stonework in the retaining walls and some old bridge foundations as you explore the reserve. You can also listen to the bell birds and trains as you make your way to GZ.
Clue 1: Near the carpark WP there is a sign describing the regeneration works in the reserve. The bushcare officers phone number is 4732AAAA
Make your way to the bellbird reserve tunnel (the initial WP).
Clue 2: As you enter the tunnel there is a sign on the right hand (northern) wall. B is equal to the digit that appears 3 times on this sign.
After finding the tunnel you will need to make you way through, beware the "bad man" on the other side
Clue 3: As you walk through the tunnel from east to west count the number of air holes (approx 20-30cm from ground level) on the left side. Include the air holes in the portal and retaining wall at the entrance and exit. This 2 digit number is CD.
Clue 4: After walking through the tunnel, to the western end, how many bricks high is the left end of the tunnel portal. ie the lower wall at the end, away from the tunnel mouth. This 2 digit number is E & F
Once you have the digits for A-F use the following to calculate the final coordinates
X = A + E
Y = C +D - E
The coordinates you seek for GZ are then S33° 44.XBC E150° 38.FY