The EA has a legal obligation to get you the best price they can. Failure to do so, or acting in the best interests of another person or body could see them lose their licence.
It's very unlikely that a local authority would commit to purchasing a property, and then be willing to wait indefinitely to close out the sale. There's little or no upside for them when they are under pressure to provide more housing as a matter of urgency.
You would need to be able to provide proof in relation to breech of contract in order to get out of your obligations.