I think there will be a second referendum with or without Westminsters blessing. If the Scots vote yes then it will be up to the UK government of the day whether or not they have the courage to comply with the settled will of the Scottish people.
Brexit was always going to put a severe strain on the Union, especially the “Boris” version which resembles a slow motion car crash. I believe, as many warned, that Brexit might just be the source of the impetus to accelerate the process of self determination for Scotland.
One thing is for sure the next few years will be very interesting!