Help please! Making a good choice between two jobs

After about three months of unemployment, today I have been told I will receive two different job offers. Obviously I want to make a decision that maximises my utility, but there are some difficult-to-quantify factors involved. Can anyone suggest a useful or clarifying perspective on the choice? What questions should I be asking myself?

As background, I’m a 36-year old male techie based in the UK. What I would really like to do is build my own startup, or join a startup that I think has good prospects. However, having done that twice, and nearly bankrupted myself twice, I need to get a financial cushion under myself before trying again. For the sake of my CV, I think I need to stay in my next role for at least 18 months. After that, I hope to be able to try something entrepreneurial again, but I want to stay employable in technology as a financial safeguard.

One job is in London, and will certainly pay more. I have many friends there, and a social network I can get back in to straight away. The pool of women I am interested in dating is much bigger there. The job itself will allow me to improve my skills, but probably not broaden them; there are very skilled people there that I can learn from. With this job, I fear being bored, and getting more and more specialised in a skill that is getting less popular.

The other job is in Glasgow. It will pay less, probably by about £15k. The cost of living difference, after tax, will probably be bigger than this—I expect I will have more money in my pocket with this job than with the London job. I only know two people living in Glasgow, so I will need to make new friends and get a new social life. Dating prospects are probably less good, but I don’t know by how much. The job itself looks more interesting, and I can broaden my skills. The job market I am in will probably be more open to me after I take this job. With this job, I fear getting depressed due to isolation, and also the long-term effect of accepting a pay cut—if I worked in London again later, would I be able to negotiate my salary back up?

Cost aside, London is a better location. It has more of everything I am interested in (including a LW meetup group!). Location and pay aside, the job in Glasgow is better. I expect it will be more interesting, and will make it less likely that I’ll be unemployed in the future.

I don’t know how to weight these factors up properly. What mistakes in judgement do I need to avoid? What approaches can I take to make the decision easier to make correctly?