If you are not from the UK or Europe, depending on your nationality, I can see why she might have some very serious concerns about the fact that you could just go home with your child and SHE might never see him again. Maybe you wouldn't do that, but it certainly happens a LOT, and I'm sure you're not unaware of that.
Do you live in the UK now?
If you were paying £1000 a month before, keep putting that into a bank account earmarked for him - don't stop doing that until he is an adult, and keep writing to him. The blog is a bit fiddly. The could be emails, they could be plain ordinary pen and paper, with photographs etc - it would be incredibly meaningful for him down the line to have all that PHYSICALLY.
Keep being consistently there for him, because if this drags out and if this never actually works out for you getting access, you still have responsibilities and you still have the opportunity for a relationship down the line with your child, and it will help him process it all if he can see that you were consistently writing to him, putting money away for him etc. etc.
We can't comment on any of the other stuff, because we have no way of hearing it from his mother's side of things.