Wonderful evocative shot.

I am too young by a couple of years to have seen the Whistlers in revenue service. Early in spring 1984, I saw a couple outside Carlisle - annoyingly, my Leeds-bound service was in the hands of a 31/4 instead.
The other 40s I saw, were on death row - at Swindon Works (1985) and Crewe Works (1986).
And much kudos for your father running a Rover P4 in 1984. I remember seeing P6s and occasional P5 on the road back in the early 1980s; but I never saw a P4. My first car was a 1986 SD1.