The bike was vandalised sometime between 16:00 on Sunday 2 August and 11:25 the following morning.
At the time, the unattended bike was located in the bicycle shed at the front right of the car park.
Police are looking to speak to anyone who saw this happen or anyone who may have dashcam footage covering the area between the given times.
People are asked to contact Guernsey Police on 725111 or call Crimestoppers anonymously on 0800 555 111.
