Chestnut Grove

We own an end of terrace house, part of six houses that are accessed through a drive way from the main road and with a plot of land in front of them that serves as parking space for all six houses. This land was owned by the Crown. Five of the six houses are owned by two of the neighbours who formed a company and decided to buy the plot of land from the Crown. We expressed clear and absolute interest in buying the land in front of our house to safeguard our access and parking rights. We got a solicitor to represent us and liase with the Crown solicitor and the solicitor representing the neighbours company. What unfolded was a sort of conspiracy that ended with the Crown selling the entire plot to the company formed by the neighbours against our explicit will. The long and the short of it is that the Crown solicitor confirms having sent an email to our solicitor with a deadline to respond and confirm our interest. Our solicitor denies having received such an email. And thus the sale went ahead without our knowledge and against our will. Now I am not sure how one can verify whether an email was sent or received. But they can't both be telling the truth. And thus we have enough reason to believe that there was serious misconduct from our solicitor as he failed to represent us in such a simple matter. But not sure where to go from here? We have a full record of all correspondence including confirmation from the Crown solicitor that they have sent that email to the correct address. The neighbours are now bullying us and trying to extort very high "maintenance fees" for the "parking space", so we need to act Please advise what options are open to us