Bryan Donkin and Clench
of Lincoln Works, Chesterfield
1900 Clench and Co amalgamated with Bryan Donkin and Co; re-registered as Bryan Donkin and Clench Ltd. Bryan Donkin, Junior continued as chairman but relinquished active participation in the management of the works.
1902 Donkins moved to Chesterfield to take advantage of the area's coal and iron industries and the area's transport links
'At the end of 1902, therefore, the whole of the works [Bryan Donkin & Co] was removed to Chesterfield, after the completion of 100 years in London. It was in 1900 that agreements were entered into with Messrs. Clench and Co., Ltd., a firm founded in Chesterfield by Mr. F. Clench in 1896, for the manufacture of steam engines of the high speed design. From 1900 to the end of 1905 the Company was continued as Bryan Donkin and Clench, Ltd., the Chesterfield works having the advantage of a central position in the Derbyshire coalfield, with blast furnaces for the supply of pig iron in the immediate neighbourhood and the service of two railways, each of which has siding into the works. At the beginning of 1906 the company was reformed under the title of "The Bryan Donkin Company, Ltd.," 
1903 'SPRING CLEANING EXTRAORDINARY. Those not initiated who stood round inspecting a small apparatus placed on a hand truck outside the L.D. and E. C. Railway Station on Tuesday last would not have thought that it represented an invention which certainly creates a domestic revolution so far as house cleaning is concerned. The invention - that of Mr H. C. Booth — has been taken up by the Vacuum Cleaner Company, Limited, one of whose directors is Mr Frederick Clench, of Chesterfield, and it is at the works Messrs Bryan, Donkin, and Clench, at Chesterfield that the apparatus is now being manufactured. The invention has only been perfected a few months, but already is installed in the Royal Palaces, the Houses of Parliament, by the Railway Companies and the chief London hotels. ....' 
1903 Catalogue issued on 1903 list of gas-exhausting plants and gas valves. 
1906 Private company. Again renamed as Bryan Donkin Co Ltd.