I believe I've found a way round the bug;
Open Minecraft and get to the rotating village screen.
Sign out of xbox live. (This should take you to the screen that's missing.)
Sign back into your account.
Hopefully this helps anyone having the same issue.
Found the solution via Sea Of Thieves another MS Game: https://support.seaofthieves.com/hc/en-gb/articles/360000425788-Mouse-cursor-not-locking-to-screen
The 3rd option worked for me:
Fix#3
1. Open the run command window (Win + R)
2. Type 'regedit' and press ENTER
3. Navigate to 'Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\'
4. If it doesn't exists, right click the editor background and select Add> Key. Change the name to 'EdgeUI'
5. Navigate to 'EdgeUI' key, right click the editor background and select Add> DWORD (32bit value), change the name to 'AllowEdgeSwipe' and set it to 0
6. Close the Local Group Policy Editor window and boot Sea of Thieves.