Where are all the treaties at , that were signed in the days of Queen Elizabeth, for example?

Answer 1

A great place to begin is at the British Library:
http://www.bl.uk/search.html

That's where you may input the specific treaty you would like to find or just search terms such as "treaties" in general.

Another place to look is Wikipedia, which maintains a page called "British Legal and Governmental Documents" at:
http://eudocs.lib.byu.edu/index.php/British_Legal_and_Governmental_Documents

Or a sure bet would be the British National Archives:
http://www.nationalarchives.gov.uk/

They claim to have "Records of the UK Government from Domesday to the present."

Happy searching.