I know that the UK came off the gold standard in 1914 to pay for the first world war, and then again in 1931 after a brief reinstatement. What I am trying to find is the actual legislation that enacted these changes. Any help please?

Currency and Bank Notes Act, 1914
http://freetheplanet.net/file_download/68/Currency+and+Bank+Notes+Act+1914.pdf%22
£1 and 10/- currency notes issued by the Treasury to replace sovereigns and half-sovereigns - redeemable at the Bank of England for gold coin

Gold Standard Act, 1925
http://freetheplanet.net/file_download/60/Gold+Standard+Act+1925.pdf
Gold standard resumed. Convertibility of currency notes abolished. Convertibility of banknotes restricted to multiples of 400oz gold bars (~£1500)

Currency and Bank Notes Act, 1928
http://www.legislation.gov.uk/ukpga/1928/13/pdfs/ukpga_19280013_en.pdf
Currency note issue transferred to Bank of England. Bank permitted to redeem its notes (>£5) in currency notes and issue £1 and 10/- notes.

Gold Standard (Amendment) Act, 1931
http://freetheplanet.net/file_download/72/Gold+Standard+%28Amendment%29+Act+1931.pdf
Gold standard suspended