A mirror check will inform your signal timing.
Signalling right with no road before end of road - If there is no road before the end of the road, then an early signal is helpful for other traffic. Be careful not to signal too early in case other road users get confused and think that you're parking up before the end of the road.
Warning - Failure to signal for following traffic within plenty of time, could force other road users to make a potentially dangerous decision through lack of information.
AT WHAT POINT SHOULD YOU SIGNAL?
Signalling right with no road before end of road. You must signal before changing course or direction in plenty of time without confusing other road users - HC rule 103.