Hello Jono,
Thank you for your message & Welcome to the UK Community for QuickBooks Online.
You may be able to upgrade using the Subscriptions section of your android app store, if not - use this link and follow the instructions:
https://quickbooks.intuit.com/learn-support/en-uk/manage-your-quickbooks-account/upgrade-your-quickb...
If you don't see the subscriptions upgrade facility either within the app store, or within your account and settings - you may need to migrate onto our direct billing rather through android, just get in contact with us through this link and we can arrange that for you.