I plead ignorance of what you described. But the accusation about the Air India Flight 182, where did that come from?
Honor killings? Show me an article.
I promise you, if you google “sikh honour killing” or “sikh honor killing Britain” you will find a number of articles.
And if you google “Air India 182” or “babbar khalsa” you will also find a number of articles.
Your skepticism is understandable. But with so many search engines available, why not try one before expressing doubt? It’s a more certain way to learn something than waiting for a reply.