Hi Steve,
The daily caps within zones 1-9 are cheaper than the relevant day travelcards, but you need to be careful if you are spending a lot of time within the system without touching out. I’m not sure where the labyrinth plaques are within each station, but if they are within the paid area and you get off a train, take a picture (selfie?), and get back on the next train, you could quite easily exceed the time allowed for a journey to where you eventually touch out. If you feel that this isn’t a problem then you will save a little (off-peak zone 1-9 cap is £10.85 versus £11.80 for the off-peak zone 1-9 travelcard). However, you would need to step back a train at Hadley Wood to be able to touch in there (and out on the way home). If you pay for a ticket to Kings Cross then that will wipe out any saving using the cap.