I'm in a similar demographic to you with similar goals. Move to London. It is a qualitatively different experience to living and working in other locations (based on a personal sample size of 4). You will be able to build a much more useful network, both professionally and socially, than if you attempted the same in Glasgow. Regardless of whether you move onto a startup or another job, you will be in a much better position to accomplish either of these in London.

I am massively, massively biased and have never lived or worked in Glasgow, but based on what you've said, unless you're acutely agoraphobic, I can't imagine Glasgow being the better option.