Dear Shrikanth ji,
Thanks for the clarification.
There was an old book titled 'Ramanujan: letters and reminiscences' where there is a copy of his horoscope (only the rasi chart). The time in the book says ''nine minutes past 6 pm''. Unfortunately, I think, the book went out of print even after the first edition. But when I was visiting some western astrology websites, I found the time 18:20. I don't know how they got this time.
However I was not aware of the LMT issue.
I am a novice