In this paper, a new low-latency communication scheme is designed for blockchain based peer to peer (P2P) energy trading. The proposed scheme ensures that the energy supply/demand mismatch information is extracted more reliably in P2P energy trading and the participants do not lose profit due to errors. This scheme allows neighbouring prosumers equipped with home energy management system (HEMS) to cooperate by forwarding the extracted information from each other's energy transaction blocks. The error performance of this scheme has been derived and compared with a direct decode-and-forward (DF) scheme, which has much higher latency. The numerical simulation results demonstrate that the proposed scheme can transfer the energy mismatch information with more accuracy compared to the direct DF scheme and achieve the expected profits when worst case error performannce is considered. On the other hand, the proposed scheme can achieve the same average error performance as direct DF with a constant SNR penalty that does not degrade with channel conditions.