Wunks, It is hard to estimate the date for No. 21153, because I do not have any receipts in this area. Therfore, I use the following indirect methodology: In my data, the highest numbered English Lachenal with a "Louis Lachenal" label is No 22717. After the change in ownership in 1873, Lachenal  & Co. labels began to be used. However, they still had a stock of circular pan labels from the previous ownership, showing "Louis Lachenal," which they continued to use on some instruments.