On the 710, on the little screen next to AWS and emergency break, is where you put your headcode in. You can make a PDF for the 710 with controls and headcodes. for example put 25LH and then 005 or something into the screen and the destination is set to Gospel Oak. and 26HL then 006 is set to Barking Riverside. they aren’t official proper headcodes but just a example.