Linda Colley has some good stuff on the topic of national identity in Britain in her works; Whose Nation?: Class and National Consciousness and Britons: Forging the Nation 1707-1837. She argues that a collective, cohesive national consciousness began to fall into place after the Acts of Union, through war and the Protestant religion between the treaty and the end of the Napoleonic Wars.

In large part, the cohesive British identity was formed from below, according to sectional self-interest, as opposed to state-sponsorship, indeed - the British government were reluctant to wind up the idea of a national identity.

An interesting point Colley makes is that the people of the smaller constituent nations - Scotland and Wales - put their own regional identity to one side and embraced Anglicization voluntarily as a means to secure their own prosperity. Thus, Colley's essential argument is that a common British national identity formed after the union, and was superimposed alongside the more regional identities which had preceded it (and had continued to exist for the most part).

On the issue of how the Scottish were viewed, for a short period, it had been the tendency of the English to view the Scottish with some suspicion, but these tensions were eased with the fall of the Jacobite Rising in the mid 18th century. Lowland Scots had mostly accepted Anglican traditions and culture and identified more willingly with the English than the Highland Scots, who were still catholic. In the same way as the Irish were viewed, it was not an issue of nationality that caused any distrust or resentment amongst peoples in Britain, but rather the Catholic religion of the Highlands and Ireland and the protestant establishment within the rest of the United Kingdom.