At the moment the SNP are riding a wave in Scotland, they have a huge electoral base.

I believe, through discussion with other nationalists, that many voted to remain simply because it was Party Policy.
I am a member, but there are a few of the policies advanced by my party with which I quite strongly disagree, but I vote SNP for independence and when that is achieved, then is the time to sort out the detail.
Although Wales has a smaller number of immigrants from within the EU they are concentrated in smaller areas where the detrimental effects on public services have become more apparent.