Ok, what witchesbrew said isn't correct. The NICE guidelines don't give you a right for anything sadly. Lots of hospitals aren't following them unfortunately and they are perfectly within their rights to do so.
What they do give you, however, is a damn good framework to challenge any decision like this.
You DO have a right to be involved in any decision about your care and to be properly consulted about any refusal of treatment. The fact that you were previously told you could have an ELCS gives you a very good case to argue, as the medical advice you were given previously may have affected your decision to get pregnant again in the first place.
I personally would definitely be asking to see a different consultant. Not on the grounds that you disagree with her decision, but because he has acted in a way that has not properly explained why she has decided to contradict the previous advice you have been given so has left you confused, upset, distressed and very anxious. THIS IS NOT ACCEPTABLE.
Even if you do not end up with an ELCS you need to know why this decision was reached so that you can feel confident in it and so you don't feel 'forced' into it. You need to feel that what ever decision is made is absolutely the right one for you.
From there, it does leave you in a better position to challenge the decision if you wish. It makes it clear you are suffering from anxiety over this and you have lost confidence in what you have been told because it is contradictory.
I would also try and find out the policy of the hospital on ELCS. Are they trying to reduce CS and do they have a 'blanket ban' on them? Basically are you be the unwitting victim of NHS politics or is the reason behind the decision medical ones.
If its the latter, then you will need to discuss the implications so you can mentally deal with this. Your mental health is as important as your physical health and if the thought of having similar problems to the ones your have had previously is causing you this must distress, the hospital have a duty of care to help you tackle this accordingly.
If the former is the case, it leaves you with the knowledge that you may have a fight on your hands and you may even want to consider going to another hospital which is more open minded. It makes you aware of whether your interests or the interests of the hospital are being put first.
You do have the right for the most appropriate care for your situation. If this means an ELCS is the best option, then you technically have a right to an ELCS. If they are neglecting this, by putting in policies which could have a negative effect on your health, you have really good grounds to fight your corner.
Being honest about it, you probably do have a fight on your hands given they are being difficult now. That said, I've seen a lot of threads like this which are similar and what happens is that they try and put as many women off an ELCS as possible but tend to relent after they are challenged by more determined women. There are a few hospitals who are just being impossible though. As a general rule, if you are prepared to fight, you will get an ELCS in the end one way or another.
Just because this first meeting has been off putting, it does not mean its the end and that the first consultant isn't basically lying through her teeth. Your meeting with the consultant is not futile. Your aim has to be to convey just why you don't think the previous consultant listened to you and understood why you wanted an ELCS. Just because you have given birth vaginally does not mean it has been successful, because if you have suffered damaged which has left you in such a bad state that it has let you struggling to cope both psychically and mentally on a daily basis this is NOT a good outcome. Do not accept what the first consultant said, because its clear this is not true to you. And your mental health is as important as your psychical health. This is what you need to stress and to ask, if they are not going to allow you to have an ELCS how do they intend to support you physically and emotionally with a VB?
The best way to fight is to be prepared to arm yourself with as much knowledge as possible and to have a partner, relative or close friend back you up when you go for your next appointment as it sounds like you need support rather than feeling you are facing this alone. It makes it harder for them to ignore why you are questioning the decision as it might give you the extra confidence to stand up for yourself.
Good Luck!