Same thing happened to me, same circumstances, same airline.
Going back to the Vanguard/Viscount, we were chatting at work yesterday and someone was recounting the tale of when a Trident was launched wheels up following a Viscount, and the Deps controller realised his error, came up on the R/T to the Viscount, just as if it was on the ground at the holding point: "xxx, pull over to the right, there's one to overtake you." He did, and it did!
Gonzo.