Also if Charles I won the Civil War in England that country would have been close to the absolute Monarchy. Same goes for James II defeating William of Orange during the Glorious Revolution
The Glorious Revolution is where the trick lies. The Bill of Rights of 1698 was the very act of parliament that made sure in the British Constitution that the monarch of the kingdom was subject to the laws of the land and could only rule with the consent of Parliament. Less than a decade before, rulings had made clear that as the sovereign, the King had the right to overturn laws as he saw fit. Now the tables were turned. The
de facto supremacy of parliament now gave fuel for better organization within it, as the person who could command parliament from within could command the growing monarchy that was soon to be known as the British Empire and its fortunes. I honestly don't think you even need Robert Walpole to have the position of First Lord of the Treasury evolve into that of a Prime Minister. 1688 will do that through any given FLT over a few decades.
But there's more! As a Swede as I should know that there was a long period of time when the Swedish Riksdag of the Estates had far more power than the British Parliament and the King of Sweden was a figurehead to a greater extent than his English counterpart. We are talking about theperiod of time we Swedes call the Age of Liberty between the death of the last absolutist king of Sweden, Charles XII, in 1718 and the subsequent Constitution of that year, and the coup d'état of Gustav III in 1772. Why was it that it was the British who had the great honor of bringing constitutional monarchy to the world and not the Swedes? The answer lies in the structure of the national assemblies. The Parliament of Westminster with its two chambers was far more simple in its composition than the Riksdag of the Estates which exhibited four levels, inspired as it was of the French system. It doesn't take a genius to figure out in which system it is easiest to gain control of the legislature and in which system it is easiest for the opposition to obstruct the agenda of the government. Additionally, the Chancery was poorly constructed as a government, and the position of its President did not enjoy the authority of the cabinet that the First Lord of the Treasury of England did.
Thus, you have two choices:
1) Make the Westminster Parliament far more complicated (which probably will mean that you will have to go all the way back to the Magna Carta, which would be an inelegant solution); or
2) Prevent the Revolution of 1688, which is quite simple to achieve: You can either keep James II from converting to Catholicism, which will prove a challenge, as James' devout mother and long exile in France will inevitably make him inclined to go through with the conversion, or, you can do what I would have done: Make Mary of Modena infertile. If Queen Mary cannot conceive, then no Old Pretender, no invitation of William of Orange, James II dies without a male heir and (assuming Mary II still dies before her father), Anne brings back Anglican Protestantism to the Crown. Rather than becoming the First Constitutional Monarchy, Britain remains a pale reflection of the absolutist French autocracy.
