First, 1745 was the date of the final section of a civil war - the (Catholic) House of Stuart wanting to get back the throne they'd been chucked off, in favour of the (Protestant) House of Hanover (note that the line of succession of the House of Hanover came from James VI of Scotland, who had become James I of England too). 'Bonnie Prince Charlie' wanted to rule all of Britain (and Ireland too), not just Scotland. He had strong support in the Scottish Highlands, but not all over Scotland - it's a cliche to note that, in the final battle at Culloden, there were more Scots on the Hanoverian side than the Jacobite.

The monarchies of England and Scotland were united, in James VI/I, in 1603. The countries were united in 1707 (still under the House of Stuart - the Protestant branch of it, which dies out shortly after). As I've said below, this did involve bribery of Scottish politicians; it was basically a financial transaction - the Scottish upper classes were paid off, and it meant England never had to worry about a land border again.