Indeed - on the Heart of Wales and Pembroke Dock lines guards are meant to check that the TPWS indicators on the stop boards have changed to flashing blue from flashing red before they commence dispatch - although unlike with RETB there are other physical signs that the token has been obtained and it's ok to continue; the driver returning from the token hut with the token in their hand (which they're meant to show to the guard) being chief among them! Traincrew on that service end up keeping an eye on white and blue signals as well as the more conventional red yellow and green (which of course come in both colour light and semaphore form).
On the ERTMS signalled Cambrian lines however, there are no signals of any form whatsoever to show the guard the train has a clear signal and is able to proceed. Instead, the driver gives two on the buzzer to the guard, and then the guard can start the dispatch procedure and close the doors.