Welcome to FT Chas767, and hopefully the first post of many on here.

I think everyone has answered your query, but also to confirm that if you are doing a T5->T5 connection on Sunday and arriving on a domestic flight you just do a bp scan at the automatic gates and then it's straight up the escalator to the departures area. No security.

EDIT: just to add, on arrival just follow the purple signs for "Flight connections T5". If you get bussed on arrival you will come in to the terminal on the ground floor and you have to go up one floor and follow the signs.