Erskine May (first edn 1844) became the classic authority, its current edition i(n 2022 the 25th edn) is available open access online.
"Hansard" is being used here as shorthand to include Cobbett's Parliamentary History (Hansard before Hansard). It is Hansard is report of what is said in Parliament at Westminster. With improving techniques for recording it has become a “substantially verbatim” record.
The Bodleian Law Library has a near complete run on open shelf. The Law Library doesn't have a copy of volume 274, 5th series of House of Lords (1956/7) nor a copy of volume 351, 5th series of House of Commons (1939). Both are available free online Lords v. 274 and Commons v.351 (There is a print copy of the latter in the old Bod.)
The volumes in the Law Library, for both House of Lords and House of Commons, are on open shelf on Level 0, the ground floor.
"While Cobbett had the foresight to initiate these important publications, Hansard had the determination and industry to continue their production on a regular basis. John Wright, who worked for both Cobbett and Hansard on the parliamentary series, was noted for his indolence, and the main burden of the work fell on Hansard, whose Parliamentary Debates was soon recognized as the standard record."
(see David Lewis Jones, ‘Hansard, Thomas Curson (1776–1833)’, Oxford Dictionary of National Biography, Oxford University Press, 2004; online edn, Jan 2008 [http://www.oxforddnb.com/view/article/12222, accessed 14 April 2014]
Cobbett's Parliamentary History
The Parliamentary Debates First Series
The Parliamentary Debates Second Series
The Parliamentary Debates Third Series
The Parliamentary Debates Authorised Version Fourth Series
Official Report Parliamentary Debates Fifth Series
The Parliamentary Debates Sixth Series
"Hansard" is being used here as shorthand to include Cobbett's Parliamentary History (Hansard before Hansard). It is Hansard is report of what is said in Parliament at Westminster. With improving techniques for recording it has become a “substantially verbatim” record.
If the Bodleian Libraries don't have the book you are looking for, we may be able to source it through Oxford's inter-library loan service.