One thing to Notice is that there is so much room in Engine Compartment. Today, manufacturers fill it up with all kind of Junk ECUs,DCUs....for what? Perhaps to save gas? or to charge extra...
OP's research is very accurate as majority of these Vans were Imported from UK after the Construction of Mangla Dam when a sizeable chunk of Population was forced to migrate due to submersion of their Lands & Houses. We brought 1 as well. Sadly, this is still ongoing due to the upraising project of MD.
When, I visited Pakistan in 2004 after long long time this all looked very Medieval to me aswell but after some regular visits...I could hardly find any fault....lol. But, where is the flaw...I am not answering it now :).
@OP keep posting this historical structures........as this is FordVirsa and museum will be most appropriate place for these in a few decades only.
Good Post and effort to get us all acquainted with History