The shooting down of the C130 is quite controversial in Argentina, as the plane was unarmed, and they claim that the footage from Nigel's gun camera shows that the cannon attack was head on, not from behind. I have not seen this myself, but I don't see why he would lie.
There are three versions of events. Lt Cdr Ward's original Combat Report, the 801 NAS History, and what Lt Cdr Ward says in his book.