Please listen to Dalbir Singh Patarkaar, he touches upon the events of '78 where he was present in the immediate aftermath of the firing and further expands on lead up to Saka Nila Tara, how the prominent Sikh leaders of the time were complicit in the attack and they mention the role of the UK PM (M Thatcher) at the time.
......in case anyone is wondering the other parts are from different speakers, some who were not in entire agreement with the events. Bibi Pritam Kaur's interviews are also insightful, she was wife of Rashpal Singh (Sant Jee's PA).
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥