I agree, if you feel FFS is necessary then it is necessary. I don't know the process there in the UK but try to get a consultation with a plastic surgeon. Find out just what they can do for you. Also try to get an estimate on price. This way you will have an actual amount to set as a goal. Try everything available to meet that goal. I don't know if it works or not but it can't hurt, try crowd funding to raise part of the money needed.
I also agree that if you are having depression problems get help ASAP. Depression is nothing to mess with. It could also be a case of too much idle time. Have you ever heard of the old saying, idle hands are the devils workshop? The same holds true of the mind and gender dysphoria. Too much time to think can reek havoc on our thinking process. Find a way to keep your mind busy and thinking of things other than your gender problems.