Great Monday @gerorgiehawkes
The password on the display will always change, but you can set your own personal password to access that machine when there is no one infront of it.
Click on Extras>Options>Security> Under the first grey header "Personal password (for unattended access)" you can add your own password, and confirm it> Click OK.
Anytime you're away from home as long as TeamViewer is on and running you can connect using the ID, and that personal password.
Hope this helps!
Whhat do you put in the space labeled 'identifier'