Overall, I'm trying to work out how wrong the Whiggish narrative for England really is. While it does seem a bit of a stretch to try to construct a continuous tradition of parliamentary constitutional monarchy that extends back to the Anglo-Saxons, it does seem like England was "less" authoritarian than other European powers by the 19th century, and even people like Bolivar commented that Spanish American independence was more difficult because they were less experienced with representative government. But then on the other hand, you have England's vehement (and perhaps even fearful) opposition to the young French republic.
So: was England slightly more "democratic" than other major European powers in the 18th & 19th century, and if so, is this the result of revolutions under the Stuarts, or an older tradition of (partially) representative government?
To some extend, yes.
England had a strong nobility ever since. You might have heard of the Magna Carta from 1215 where King John Lackland had to grant several rights of constitutional character. Was it democratic after the Civil War?
The elections were not equal, people had to own property to vote, (later only married) women were excluded and colonies were not represented. But England never developed into an "absolute" monarchy like most European states did until the 18th century, the parliament maintained its rights and, which is maybe even more important as it was something valuable for all people, it was the only monarchy where freedom of press was granted. This certainly allowed it to react to the people's demands in a more peaceful way that allowed for compromises. On the other hand, there were already some European Republics in the time between Napoleon and the First World War: Switzerland, France (1848-'52 and as of 1870), Portugal (as of 1910) and the Free Cities (Hamburg, Bremen, Lübeck, Frankfurt until 1866, Cracow until 1846). And the conservative German Empire allowed (men!) free and equal elections since its foundation. Rather than being a "democracy", caused by its early industrialization and non-absolutistic history, Great Britain had a strong liberalism and pluralism in its aristocratic and economic upper-class elite that had a relatively well-functioning platform: The House of Commons.
The Congress of Vienna (1814/'15) after the Napoleonic Wars introduced the "Vienna System", a multilateralism-based diplomatic system between the four (later five, including France) remaining great powers. It consisted of numerous treaties that were tied together as one sothat a breach of contract by one great power would mean a breach against all great powers at once; its purpose was to make it impossible mainly for France but also for any other great power to become too powerful. A different system that existed parallely to the Vienna System, but was never part of it, was the Holy Alliance between the kings and emperors of the conservative great powers Austria, Prussia, Russia and France during the restoration. These great powers agreed to protect each other against revolutions of any kind to retain their absolute power; Russia for example crushed the revolution in Hungary in the Austrian Empire in 1849. Great Britain did not join the Holy Alliance and prevented its incorporation into the Vienna System for two reasons that show very well the difference in her political system: The King of Great Britain did not have a mandate to join the alliance due to the role of the British parliament and was formally unable to join, and Great Britain bound by its powerful public opinions spread through the press was neither able nor willing to protect absolute monarchs against revolutions of their own people.
That being said, Great Britain sometimes still had good reasons to oppose national revolutions, most importantly, its conflicts with its arch rival Russia (see: The Great Game). For example, especially before they got the Suez Canal, Great Britain ruthlessly fought for the continued existence of the Ottoman Empire that granted her trade privileges. During the revolution in the Romanian Danube principalities, Moldavia and Wallachia, that were autonomous parts of the Ottoman Empire, Great Britain and Austria tried everything within their power to stop it sothat Russia wouldn't get a footstep on the Balkan.
Some literature:
Anderson, The Eastern Question 1774-1923.
Baumgart, Die Orientalische Frage.
Baumgart, Vom Europäischen Konzert zum Völkerbund. Friedensschlüsse und Friedenssicherung von Wien bis Versailles.
Riker, The Making of Roumania.
Langewiesche, Europa zwischen Restauration und Revolution 1815-1849.
Lentz, 1815. Der Wiener Kongress und die Neugründung Europas.
Schroeder, The 19th Century International System: Changes in the Structure. In: World Politics, 39 (1986), S. 1-26.