Post WWI they were deep into Aluminium/"Duralumin" and were in the dirigibles by 1920/1921:

http://homepage.ntlworld.com/forgottenfutures/vickers/vickers.htm

Some Crayford history: http://www.crayfordhistory.co.uk/index/history-of-vickers-crayford/

Kind Regards,

Raimey
rse