THE PLOT IS REVEALED
*a big heap of bombsite rubble brought from London to help to harden ground :: I read that in WWII in 6 months 1700 freight trains carried 750,000 tons of London bombsite rubble to East Anglia to make bomber runways.
*broken pieces of a bombed dockland school's concrete playground :: I read of a case in reality where in WWII some bombsite allotmenteers were assigned land where a school had been bombed out, and they broke up its concrete playground to get more land to cultivate.
AFTER THE WAR
THE OLD PLAN LEFT SOMETHING
*and carried on to RAF Northolt :: In the real world (OTL) she landed on the big airport at Heathrow.
NIGHT ON THE NORTHERN FIELDS
*Aurora Hattonensis :: In reality Patrick Moore had a slang name "Aurora Bognor Regis" for a night glow from Bognor Regis town which interfered with his observing at his observatory at Selsea.
END OF AN ERA
*along the motorway ... got off at the junction north of Sipson :: Without massive airport traffic, I am assuming that the M4 motorway would have an ordinary compact junction with the road going north out of Sipson, and no airport spur.
LIFE GOES ON