Puritans were blocked from changing the established church from within, and were severely restricted in England by laws controlling the practice of religion. Their beliefs, however, were transported by the emigration of congregations to the Netherlands (and later to New England), and by evangelical clergy to Ireland (and later into Wales), and were spread into lay society and parts of the educational system, particularly certain colleges of the University of Cambridge. They took on distinctive beliefs about clerical dress and in opposition to the episcopal system, particularly after the 1619 conclusions of the Synod of Dort they were resisted by the English bishops. They largely adopted Sabbatarianism in the 17th century, and were influenced by millennialism.
What group was very much hampered in England from making changes? (If the question is unanswerable, say "unanswerable")
Puritans