I think the Premium Service proposal because you asked for a telephone call. You don’t have to take it up.
The fact that you may have been going to buy the property and have now changed your mind is not relevant with regard to the rent.
At present, the legal situation is that he is stuck with you until the end of March 2018 and you are liable for the rent until then or until he gets another tenant to replace you if you just move out.
He is under a duty to try to get another tenant. Meanwhile you are responsible for the rent.
The difficulty facing you is that your only bargaining chip to go early is that he wants you to go but he only wants you to go when the property is sold. On the other hand, you are entitled to stay until the end of the term and the buyer would buy the property subject to your tenancy.
The only way out of this is to tell the landlord that unless he lets you go now, you will have no option but to stay until the end of the term and hence, he will not be able to sell with vacant possession.
Basically, you are going to have to bluff it.
You can tell the agent that so that they are not misleading anyone who enquires after the property.
Can I clarify anything else for you?
Please rate the service positive. It doesn’t cost you anything but helps me greatly.
We can still exchange emails. Best wishes. FES.