I may have this wrong too, but according to Google "YTYC" is a BT engineering code (BT formerly being the GPO - General Post Office). Codes are used for physical locations and YTYC is linked to Twycross. Codes beginning with the letter Y were radio-related sites...
https://en.wikipedia.org/wiki/BT_site_engineering_code
Of course "YTYC" could have several meanings "youth training something something", etc. Good luck with your search. Maybe someone on here can offer something more.