As you're focusing on English History, I guess it's more of a difference between the CofE and the RCC? If so, this would be a good place to go to
Worship-Book of Commom Prayer-Articles
If it's more generic between protestant and catholic, this will still be useful to you. These are the 39 articles of Religion of the Church of England. These were written back in the day and are the individual things that the CofE believes. Some of them show the differences in belief quite clearly as they are arguing against some RCC beliefs/practices;
Art. 6 - Roman Catholics use the apocryphal/deuterocanonical books and view them in the same light (fully canonical) as the 'normal' books. Protestants either don't use them or treat them differently (as the CofE does).
Art. 18 - At the time, there was persecution, and protestants were branded as heretics, they were told that they would not be saved as they did not belong to the RCC. This argues against that.
Arts. 19 & 20 - Start to put the view over that the RCC has gravely erred and has done things 'repugnant to the word of God'. This view is not held by the RCC in so cheerful a manner.
Art. 22 - Protestants do not believe in Purgatory
Art. 24 - Back to History, at the time RCC mass was carried out in Latin. Protestants have always emphasised the accessibility of the Bible and church services.
Art. 25 - Protestants (of a more traditional viewpoint) have two sacraments (some less traditional prots don't recognise sacraments). The RCC has 7.
Art. 28 - Protestants don't believe in transubstantiation, there's that word 'repugnant' again.
Art. 30 - It was common practice to offer congregations only the bread in the mass. Protestants have always taken both the bread and wine (except in exceptional circumstances when this has been unwise; last year the CofE prohibited the wine to congregations from one cup due to the swine-flu outbreak)
Art. 32 - Protestant clergy have always been allowed to be married.
Art. 37 - At the time, Roman Catholicism was established religion across much of Europe. Protestants (in England) broke with this. Also the Pope is recognised by RCs as the leader of the Church. Protestants do not recognise him as the leader of the world's Christians, and do not accept his authority.
Hope that helps to start with.