For anyone interested in the Grubbs there is the book by Ian Glass: "Victorian Telescope Makers Te lives and letters of Thomas nd Howard Grubb", However only one out of 250+ pages refers to photographic lenses the rest being predominantly about the telescopes and other scientific instruments that the Grubbs were both famous for. Thomas Grubb seems to have been interested in photography by at least 1850ish but the 1866 contract for the Great Melbourne Telescope (worth a lot back then) seems to have been the factor which decided the future direction of business and from then on photographic lens production appears to have become somewhat sporadic, often probably bespoke, and astronomy's gain was photography's loss. The Grubbs may well have been 'instinctive' opticians with an understanding of what they were tying to achieve opticalyl allied with practical and precise engineering skills which enabled them to make things happen within the technial confines of the times they lived in.