re :I've gone into Tools > Account Settings > Server Settings > Advanced and looked for the option to check "Include this server when getting new mail" but it's not there.

It will not be there because only POP mail accounts which have been specifically as deferred accounts will see that option. In other words set up to use a Global Inbox like the 'Local Folders' mail account Inbox.

You are talking about an IMAP mail account.

Checking every minute is really too much. IMAP mail accounts will be checking and synchronising a whole bunch of subscribed folders. They do not work in the same way as POP mail accounts.

Tools > Account Settings > Server Settings Set to check less frequently eg: 5 mins is really the minimum to set. This allows plenty of time for folders to fully synchronise. Also select the option 'allow immediate server notifications when new messages arrive'. This means the server will contact Thunderbird imap account when new mail arrives if it arrives in less than the set checking period, so you do not need to keep manually checking.

With IMAP servers that don't support PUSH, i.e. immediate server notifications, you can manually force a check for new mail by selecting another account in the Folder Pane, then selecting the account you wish to check. There is also an add-on that improves on the built-in Get Messages function:

https://addons.mozilla.org/en-US/thunderbird/addon/get-selected-mails/