Will the MSC help you get a job? Will ot be £10-20k worth of help?
You say you have depression and anger issues. What are you doing to solve those? If you arent careful they can cloud your whole approach and come across in interview. Dealing with these are just as important as your job search.
If the type of experience you want isnt available, what sort of plan/ efforts have you done to obtain it? Everyone starts somewhere. Are you using Linkedin and networking amongst contacts? If you cant do exactly what you want, then what about getting the next best thing to make it easier to get onto the level above? Sometimes you have to take small steps and just build towards where you wish to go.
Unless it was Oxbridge or Imperial, then you might wnat to check whether your qualification will really enhance your pospects as you wish.
How many jobs have you applied for? How many first and then second interviews?
You need to get people you trust help you identify where your weak points are. Look at every aspect of the process. there are always things you can improve.