Interested to read this. My recollection of the "Rules of the Game" as a Signal Engineer for 41 years (I've been away from the UK for 20) was that if you provided a "Theatre", it had to give an indication for all routes i.e. the "main aspect only" wasn't allowed. I think there also used to be a 40 MPH restriction?Approaching Blackburn from the Preston/Bolton direction the signals before Blackburn Bolton Jn give a wide array of indications: "1" for platform 1, main aspect only for 2, "B" for 3 (bay), "T" for 4, "G" for the goods. There are also several subsidiary indications depending on the signal in question.