Diddy :
The area on the northern edge of the airfield you describe is that known as "Northside". This was the original terminal area from the day Heathrow opened, and they were still all in tents, then operators steadily moved over to the Central Area until the intercontinental operators were last to move out to the Oceanic Building (now T3) in 1961. Others can correct me but I believe most of the terminal buildings at Northside were wooden/temporary structures.
The area nowadays is occupied to a considerable extent by the large Pink Elephant car park. The original rough concrete surface of the ramp is still in use there for car parking, and if you walk around and look closely you can identify where aerodrome light fittings etc have been removed.