Hi, ncraniel. I have a brief response for you based on a reading of R.A. Palmer's classic "Age of Democratic Revolution." One of Palmer's guiding ideas in this book is that the revolutions of the 18th and 19th century find their context not in one particular country, but in a democratic movement happening across the Atlantic world. So, America's revolution had precedents - Rousseau's Geneva, for instance, or the agitations led by John Wilkes in the UK demanding a more representative parliament. Likewise, it fed ideas back into the great democratic upsurging of the 18th century.

Remember first of all that the American colonies began as a part of the body politic of the UK. Their independence by itself already marked a great rupture in British political and social thought.

In the sense of changing the scene in the UK home islands, the American revolution fed back to the UK, and indeed to France and many other countries, the idea that "there were two levels of law, a higher law of constitution that only the people could make or amend, through constitutional conventions of bodies similarly empowered; and a statutory law, to be made and unmade, within the assigned limits, by legislators to whom the constitution gave this function." The UK and other European countries inherited this idea from America: the people were a constituent power who deserved to decide their own constitution.

This idea was quite literally brought to Ireland aboard John Paul Jones' ship Ranger, which landed in an undefended Belfast in 1778. Afterwards, Protestant volunteers companies began to arm. These were at first countenanced by British authorities but later became more rambunctious and demanding. England was forced to grant the Irish Parliament (that is, Protestant Irish) independence in 1782.

The aforementioned reform movements of John Wilkes - the Association Movement, so-called for the local associations that formed to demand change - also picked up steam in England proper, fueled by the tax burden of war, the fact that England was losing, and the dissatisfaction of local landowners. The formulation of the American revolutionaries gave their movement shape. Charles James Fox, a Whig MP, became active in this movement and, eventually, Prime Minister William Pitt tried to move a reform bill in 1785. Though modest in scope, seeking only to buy and redistribute a few rotten boroughs and modestly expand the franchise, it failed. Serious reform would have to wait a generation, but the American revolution had certainly changed the debate.

Again, not my expertise, but I hope this was of interest to you!