From Paul Cairney (2011) The Scottish Political System Since Devolution (Exeter: Imprint), pp.147-8:
"The monitors discuss, periodically, Scottish attitudes to who can claim to be Scottish. For example, in 2001, 75% respond that people who immigrate into Scotland cannot be considered Scottish, compared to 15% saying that they can (Curtice, May 2001: 24–5). There is some movement by 2005, but the majority (54% plays 33%) still require more than Scottish residence. In 1999 only a small majority believed that ‘people who live in Scotland but were not born in Scotland should be entitled to a passport in an independent Scotland’ (Curtice, May 2001: 24–5). This rises only to 62% by 2004 (33% against) among ‘majority Scots’ (born in Scotland, not English, not Muslim, and without a partner born outside Scotland—Curtice, May 2004: 23; Miller, 2008: 4). Further answers (from all respondents) suggest that English residents in Scotland should fake a Scottish accent and keep their birthplace secret if they seek acceptance. While 44% ‘would regard someone who was born in England but now lives permanently in Scotland as “definitely” or “probably” Scottish … 70% said that they would regard a non-white person with a Scottish accent as “definitely” or “probably” Scottish’ (Curtice, May 2004: 23). The latter rose to 90% by 2005, and the colour of the Scottish-accented person’s skin makes no difference (Curtice, September 2006: 30). However, the response differs if the respondent knows that the person in question was born in England; only 44% think that someone born in England with a Scottish accent is Scottish (42% if that person is not white, 15% if they have an English accent, and 11% if they are also not white—Curtice, September 2006: 32). Overall, as Curtice (September, 2006: 31) notes: ‘It would seem that the children of immigrants to Scotland who are born and brought up in the country are readily accepted as Scottish, irrespective of race or colour, but that their parents will to some degree be regarded as “outsiders”’ (see also Curtice, May 2002: 29–30 on mixed Scottish attitudes to immigration; Curtice, November 2003: 22–4 and January 2008: 51–2 on perceived and expressed levels of prejudice). However, perhaps some comfort can be taken from Scottish attitudes to English people. Curtice (August 2000: 7; August 2002: 18–19; May 2006: 37) notes the generally high proportion of Scots who like the English and would support England in the (football) World Cup or European Championships (as long as they don’t ‘lord’ it over the Scots—Curtice, January 2006: 56) There is also no evidence presented to suggest, in surveys of social capital, that people are less likely to ask an English neighbour if they can borrow a sink plunger or £5 for milk (Curtice, January 2006: 62–3)."
The notes in brackets refer primarily to individual 'Scotland Devolution Monitoring Reports' which can be found here (up to 2005) and here (2006-9). This UCL project ended in 2009, but similar work on national identity and attitudes is still being done by people like John Curtice and David McCrone/ Frank Bechhofer.