In the past parliamentary elections involved voting in public, and often significant bribery, so there was great interest in how people voted. As a result many poll books, recording who voted, and for whom, were printed and have survived. In different constituencies there were different rules but there was a qualification - usually the value of the property owned or occupied.
Quite often the poll book from one election would be used as a canvassing book for another and the example for Sandridge voters in the 1832 poll for the Hertfordshire County MPs includes some deleted entries - presumably because the people concerned had died or moved away by the time of the next election.
Old habits die hard, and after the Reform Act bribery continued and and after the 1850 election the parliamentary report on "the existence of bribery in the Borough of St Albans" includes lists of voters in the 1847 and 1850 elections - and verbatim reports of the evidence given by many of them.
The known surviving poll books, and their locations, are listed in the booklet "Poll Books c1696-1872: A Directory to Holdings in Great Britain" by Jeremy Gibson and Colin Rogers - published by the Federation of Family History Societies.
If you can add to the information given above tell me.