The challenge is to make Scotland have a hegemony over the British nations; making it the premier cultural, economic, etc force in Britain. Per the OTL, this is rather more England's case.
1) Lord Murray convinces Charles Stuart to head for London in 1745 causing George II to flee to Hanover. A token force of 1500 is defeated by Murray at the Battle of Kensington wins over the British just as word of the French landings at Maldon under Marshal Saxe distract Lord Howe and force him to be in two places at once. While Howe acquits himself extraordinarily well by all sources, George II is captured while trying to flee to Hanover and Charles Stuart is crowned Charles III. His reign lasts only eight months during which time he becomes very ill with consumption, permitting his Roman Catholic Cardinal brother Henry to return to London as Henry IX. He uses his influence in the church to have the marriage of a very unhappy Hanoverian Princess Mary annulled in exchange for the right to marry her himself. Although neither had planned for a family (she being 36 and he 34 at the time and allegedly homosexual), they began the "New Stuart" dynasty. Henry, as well as his crown prince/future king James III, wear tartans about the capital and spend a great deal of time lauding Scottish culture. James III in particular (reign 1799 - 1836) solidified the Scottish trends with leadership during the Napoleanic Wars by constantly wearing his Tartan about. That pattern of yellow, blue, and finely woven colorings (OOC "Prince Edward" style) became synonymous with higher culture. Once football was taken as a Scottish pastime it rapidly spread to England, as did other elements of Scottish culture. While Hagas and other choice cuisines remained uniquely Highland, the evolving "American" influence from the Colonies and their Celtic roots reinforced the trends accordingly. The "Deathbed" Act of Confederation that released the 35 colonies to form the Union of North American States (out of Philadelphia prior to the move to Liberty City in 1888) only heightened the Scottish influence, especially as the post-mortem remembrance prior to the coronation of Arthur I (1836 - 1878) noted.
2) William Wallace smashes the English at Falkirk and sets the stage for a gradual takeover of much of the rest of England under various successors. By 1660 all that remains of England is Derby and farther south, eventually a civil conflict is used to bring the whole under Scottish control.
The challenge is to make Scotland have a hegemony over the British nations; making it the premier cultural, economic, etc force in Britain. Per the OTL, this is rather more England's case.