My wife's grandmother was a Comyn Ching. Are you related to this Ching family? William John Ching, Sr (1792- 17 Mar 1837) married on 23 Aug 1821 Mary Ann Comyn (1802- 3 Mar 1878).He was a barrister. They had at least 5 children-- 3 daughters who never married and 2 sons, William John Jr. and Comyn. We know that the two brothers quarreled and it may be for this reason that Comyn Ching (his full name) named each of his children like this, Marion Emma Comyn Ching (the eldest who died young). She was born in 1870. Notice that he did not hyphenate and so make the surname Comyn-Ching, although this has often been done subsequently. Comyn's descendants have followed this tradition to the present day and only his descendants are Comyn Chings, in fact one of his daughters also incorporated Comyn into the names of her children. William John Jr's children are plain Chings. So the answer to your question is 1870. Comyn Ching was an industrialist in London and his firm(s) are still in business today and still managed by Comyn Chings. You can check this out by Googling "comyn ching". Since one site you may get says the firm has been in business for 300 years it must have been taken over by Comyn and renamed in the mid-late 19th century.