Establishment of Diplomatic Relations by U.K., N.Z., Aus

Are there any websites which provide the full texts of the documents promulgated whereby the U.K, N.Z., Australia, South Africa, Canada, etc. (countries with some historical connection to the U.K.) established formal diplomatic relations with other countries?

I am researching the content of such documents, so I hope to collect a number of real world examples.

Any relevant URLs would be appreciated.

Don’t have any exact URLs, but for Australia you could probably start at naa.gov.au/