Technical answer to this:
You do not have the RIGHT to a c-section under British law. However if you have medical reasons to have one you should get one and you have the right to the appropriate medical attention in this country.
Which actually makes the situation very unclear rather than simple and straight forward!
Whilst NICE update to their guidance says all women should be allowed a CS if they request one even if there is 'no clinical indication' (Note: this is not a RIGHT as it has been widely publicised in the press), the NICE guidance is only advisory and many hospitals have actively dismissed it and are following a policy of deliberately going against it in several respects.
Further to that, what constitutes a 'medical reason' is wildly open to debate. At the moment, many doctors only consider a 'medical reason' to be something that is physical. Even the NICE guidance, whilst stating that the reasoning behind their update is to reflect the fact a request for a CS is very often for mental health reasons or that being forced to have a vb against your will, in some cases, results in damage to mental health, term requests for a CS on these grounds as being for 'no clinical indication'.
Other doctors are considerably more progressive and living in the 21st Century and realise that mental health considerations are a health reason and a very valid reason to at least consider and take requests for a CS a lot more seriously - and women who do request a CS should be given extra support so they feel comfortable with a VB or should be granted a CS if they still feel unable to go ahead with a VB.
So in terms of a VBAC, yes they can theoretically force you to have a VBAC, because its not a medical procedure so you don't get a choice about consenting to it, as its what will naturally occur if they don't intervene even though there is risk attached to it. It can and does happen - rather more frequently than it should be.
More practically though, if you adamant you want a CS the chances are you'll be able to get one. You might find it easy, however you might be refused initially and find yourself with a real battle on your hands. If you have a consultant who is being obstructive - CHANGE. I've seen loads of women on here be in a situation with an unsupportive consultant, who have managed to eventually get a CS after seeking a second (or third) opinion.
The truth is, the reality of this at the moment, is that it doesn't matter whats in the NICE guidance. Its a total NHS lottery about what your local hospital policy is, and what the attitudes of the individual staff you see are.
Good luck, I hope you end up either managing to get proper support you need to have a VBAC or getting the CS you feel you need. If you get neither you are being let down and not given the care you do have a RIGHT to.