From the way I read your question, about nine people own various parcels of a plot of land that they all propose to individually sell to a Housing Association who would then build houses on the whole piece of land.
If you have anything worthy of a legal claim to a right of way, it will be on your Land Registry title (or deeds if not registered). It will explain the nature of your access entitlement and it should be cross-referenced on your title plan to show the general position of the access points and the route over the land.
If it isn't there, you haven't any hope of a claim unless you've been doing it for over 20 years continuously, when you could seek to claim any easement now (but you'd have to employ a solicitor to help you do it).
If it is shown as I describe, you should contact the owner(s) of the land to point out your right.
If they want to move the access (other than by a tiddly amount), they are going to have to ask your permission officially, and get the position of the new easement officially registered both on their land title and yours.
The business about the width is possibly more problematic and it will depend on what the words on the Title Register / deeds actually say. One can't go scaling a width off the title plan. It might say 'the right to pass/repass on foot' and whatever. If it does but there is no width specified, you are in for employing a solicitor to help, i'm afraid, if you want to seek to defend a specific width. One possible advantage for you could be that HAs do not often go about deliberately alienating communities in the areas in which they do business, so contacting them may result in them being understanding.
Finally I suggest you deal with this BEFORE the HA does any deal with the land owners, as what will happen is that planning consent will be obtained first - and the route of this right of access needs to be considered in the context of the planning (although it has no direct bearing on the planning decision).