Originally Posted by
KARFA
I think the non-escorted route involves going on the TTS to T5C, staying on, and then coming back with the arriving passengers to T5A so you are in teh arrivals stream. You will need your passport to get across the UK border but you can get landside using this method and you don't have to wait.
is OP not flying domestic, thus does not need to pass border control?
(disclaimer: I do not fly any UK domestic but have had no issues leaving the sterile area of the airport in Canada/USA/Mainland China.)