I noticed your name popped up as a new member and hoped you were related!
Many thanks for clearing this up. The possible connection was published in Andy McConnell's 'Miller's 20th Century Glass' but I really wasn't convinced. While I would like to attribute this pattern correctly I feel this data might be lost forever.
I am aware that your grandfather was quite prolific from about 1930 and has always been credited with Spiderweb (1934) and Lotus (1948), the latter just before he took a full-time post at the RCA, I believe. However, Robert has also been attributed with the Waverley and Britannia designs - see my web site www.chanceglass.net
for more details. Again, I am unsure but would welcome any guidance on this matter.
Please feel free to e-mail me privately, if you would prefer.