Peter, out of respect to your service to the nation, and recognising the suffering inflicted upon you by successive Tory government - both red and blue - let me share this with you.
Only the tenant may exercise the right-to-buy. Your discount will reflect all your years as a social tenant, regardless of where you were that tenant. You will also qualify for a consideration for your years in service as if you were a social tenant. Therefore it is to be expected that you are due a full discount (which may have a higher value if Shapps ever releases the findings of his 'consultation')
Another person may purchase with you if they can prove they have been resident with you for over a year. In your case, a much younger family member may be more in a position to secure a mortgage with you than you would on your own.
There are not legitimate companies of the kind you enquire about.
Now, let me share some anecdotal knowledge from when I was Chair of Housing at a certain local authority in the bad old days of the Tory Right to Buy in full vigour.
Such was the clamour to take advantage of the massive tax handouts, children stood as guarentors for their elderly parents. Others took second mortgages on their own homes and used the money to fund their parent's purchase. Others simply claimed to have lived in the home for the required period and led the purchase. The Council only had to be satisfied that the tenant could secure the funds to buy the home, not how those funds may be secured.
There is a difference between now and then. Those 'children' were able to take advantage of the massive relaxation of financial regulation and the political pressure to divest council housing at any cost. That means it was easier then to take advantage of the system so that non-residents and extended family members could effectively exercise the Right to Buy on the tenant's behalf, and acquire the property when the tenant died.
Now the bottom line - you live in a bungalow. If this is designated elderly accomodation, or special needs adapted accomodation, you may have no right to buy, even if you transfered with a tenancy that preserved your right to buy. Also, there is likely to be much higher vigilence of claims of others living with you than if you were in an alternative form of property. I suspect that you can not buy your home for this reason.
My advice then is, as angry as the situation makes you, don't lose your own principles, sit tight, but remain an ever growing thorn in the side of the establishment that attacks you and so many of your peers.