Thanks, Sunny for employing the infra-red technique to check on the underside markings. I agree that there are enough similiarities to suggest that the last pic shown is very likely the Rounded Six Line Blue.
My doubt is still on the one with dark brown and purplish patch on the upperside. C&P4 has upperside pictures of both male and female of the Rounded Six Line Blue, and none matches the pic I took.
Horace