Common Tit

Thank you so much Lenny, i will update the spotting.

Yes Rob.Maybe just an odd one.I thought your other photo was also H.erylus.
I have looked at many of these blues and there seems to be a lot of variation
even in the same locality.My garden for instance.I've had a look in Pisuth Butterflies of Thailand and can't see it being anything else,plus your's looks a nice fresh specimen.The book is OK but photos of pinned insects.

Hi Lenny
Firstly thank you for ID, common tit was also my first idea but what is throwing me is the small semi circular marking at the front of the hind wing. I can't find any images showing this.