If the Labour leader believes his MP's arent speaking for their constituents (a vast majority of them arent, considering the remain MPs in Leave areas are), then he can just ignore the MP's if he wishes.
The Vote was also unbinding, how very unfortunate.
You could take that view, but it seems to me that it is important for a leader in parliament to command the support of his MPs.
I agree that there is a disconnect between many people and politicians (which brings into question how representative MPs actually are), but I do not agree that this is defined along some hard-left fault-line.