Dear Win,
Now this is interesting. I've been actively researching the Chills in Penang in recent days, and my Mum remembered that her mother referred to an Uncle Walter Chill at some point when recalling her childhood in Penang. I also know that my great grandfather Jack Mason had a Eurasian mistress in the latter part of his life - his wife, nee Dorothy Chill, was aware of this, and possibly the reason why he died was because he fell ill while up in the foothills with his Malay lady, and it took a day to get him to hospital - where he died horribly from appendicitis...
So, I wonder if your grand uncle was the same person as your Walter Chill? If you know anything, I'd love to share info with you. I've just found out from a photo that it is likely that my great grand uncle Monty Chill was probably of Malay descent - he looks like he is related to somebody from Sumatra or Java, so who knows - but he's definitely NOT white British!
Hope this gets to you soon - I'd love to hear from you.
Best wishes,
Jessica