Re British identity in Scotland you have to take the census results with some caution. It showed 62% of Scots identified as Scottish only. 18% identified as Scottish & British. Only 8% identified as British. I imagine the bulk of folk who identified as British only were probably not Scottish born.

However there are two things to note. The question only gave folk the chance to be either Scottish Only - or Scottish and British. This was like having to give Scottish and British equal billing. Other polls have asked a similar question but give the option to put Scottish first with British second. They tended to show more folk choosing British to some degree - but not giving it equal billing with the Scottish identity. Hence it can be how you ask the question. Though Scottish Only still tended to show about 40% odd or so.

Plus it is secondly what is meant by British identity. If people think they are being asked to define their actual nationality as British then they are less likely to do so - especially for the 50%+ percent or so who favour independence! However many like myself would identify as Scottish by nationality - but I am happy to view myself as British in a geographic, familial sense. Like Swedes and Danes are Scandinavians etc.

As said previously people will identify themselves as they identify themselves.