To sign off all the 50 geocaches in the Park you could stay in the Courtyard House. To book it just visit the previous link. Enjoy the fantastic harbour views to the NE and NW.
Courtyard House
View to the NE
View to the NE
Gate opening hours
Daylight savings (summer): 6:00am - 9:00pm
Non daylight savings (winter): 6:00am - 7:00pm
There is 24hr pedestrian access.
The cache is a 200ml plastic bottle.
Update 9/12/2017: The hint has been changed.