On why he concluded that Indira Gandhi knew nothing about the suitcases of money that the KGB was providing the Congress Party.
That was the evidence. That's what it said. There was no reason to doubt that she had any knowledge of the source (of fund going to the Congress).
Why the book doesn't reveal the names of the Indian agents or newspapers who received KGB money.
The publishers have legal reasons and that was the code followed in my earlier book on the KGB activities in Britain and the US. The Times apparently decided to publish excerpts on India, which I appreciate will be of greater and wider interest to the people than anything about, say, Yemen or Syria.
Did he seek any collaboration from sources in India?
I have given at the end of the book about 80 sources. Now so much is available through the Internet and indications are virtually academic tested. Complementary sources have been used for collaboration. But the fundamental question is about the reliability of the source. There are huge reasons for trusting the source and the British intelligence and security had concluded that the "archives" were of tremendous value.
About what the KGB did in Pakistan.
Yes, it is in the book and also about the KGB operations in Afghanistan. It was difficult to operate in Pakistan under military regimes.