Police say the malicious damage was caused between the park closure on Tuesday 3 March at 18:45 and 07:30 the following morning, and are now appealing for more information about what happened.
Other park property was also “disturbed”, the force said.
Officers are asking any witnesses or those with more information about the incident to contact 612612 or the independent charity Crimestoppers anonymously on 0800 555 111 or via their online form.