The timezone on the iPad should be the same as the calendar. Below is how to change the timezone for these, however we suggest leaving these to automatic wherever possible.
Go to Settings > General > toggle Set Automatically
Go to calendar.google.com > select Settings and Sharing by click the 3 dots when hovering on the calendars name > select timezone.
Our support is just an email away. Please send your questions to get-support@centralise.io