I just need to know where I stand legally, Do I have to pay the backdated £750? It does not make sense to me that I should have to pay when I essentially lived in limbo not knowing whether I had an agreement in place or not, surely a contract is only legally binding once signed by both parties?
It is a lease renewal / rent increase contract
Yes it is.
The original lease was £1050, the Memorandum of Renewal shows £1300