Where abouts are you in the UK?
Support for someone in your position who has a severe lack of trust in the medical profession is few and far between but there are a few places that seem to 'get it'. I have my own issues with it, to the point that I have had to seek advice over it and its a problem for me prior to getting pregnant.
If you intend to go down this route, please consider the possibility that if it doesn't go to plan that you might end up in a situation where your mental health or whether you are putting your child at risk might be an issue.
To me the issue is very much about you feeling the need to be in control and to be able to make your own decisions rather than be treated in a certain way. ELCS are usually talked about as the solution to this; I don't think this is the case for a second, but you need to be given an alternative that works for you and until you find that, I can understand why this option looks an attractive one.
In terms of legality, there are issues if you deliberately and knowingly avoid medical advice during pregnancy for example if you deny you are pregnant. In terms of consent this could potentially be used against you. You have a right to refuse treatment if you wish, as long as you are considered competent, but to actively avoid any medical involvement, it may identify you in some way as 'at risk' by assessing you as not competent. The point is 'they' (and I think you understand why I have phrased it like that) need to feel reassured that you fully understand the risks to you and yourself and are not acting in a way that is not in your best interests and put you at extreme risk perhaps due to your inability to assess that risk properly due to your fears. (Eg in exactly the same way that some one who was expressing suicidal tendencies might be assessed as a risk to themselves).
On a personal level, one of the things that has been said to me was that that my fears did necessarily just impact on the birth. If you have issues with the medical profession then how does this affect your child? Does this mean you would avoid seeking medical attention for them under certain circumstances. In which case are you putting yourself in a position where you might be considered as posing a threat to your child? Tough question, but be honest with yourself over it, and not anyone on this forum.
I don't mean to sound alarmist. Far from it. What I'm trying to say is you need to do your research and fully understand the implications of what you are thinking about, and you need to fully explore other options that may be an alternative to you.
The key part is you need you address what is the very core of your fear and how you feel you can cope with that under your terms. I'm not entirely sure you are doing that, as you are adopting a coping strategy of 'avoidance', which is rarely a productive response.
My advice. Find somewhere prepared to listen and proactively response to your demands no matter how 'nuts' they might consider them. If they think you are really seriously considering this and therefore have considerable concerns about you, it might surprise you how far they may bend over backwards to help you under your own terms. Not everywhere will be like this but there are a tiny number that are. Thats your problem, finding the right place where you can discuss your concerns - not counselling - so they can put in a plan that works for you. (I refuse to go down counselling route fwiw due my concerns over that too).
Good luck whichever approach you take ultimately.