Accommodation requirement

Hi
I have a question about the accommodation evidence for a UK fiancé visa. I am Turkish. My UK fiancé is purchasing a property and has the contract for sale. We have enclosed details about the property as well as confirmation his offer was accepted from the vendor, and the mortgage offer document.
Is the signed contract enough to satisfy the accommodation criteria.
He hasn’t completed on the property yet though, but we want to apply ASAP and I was wondering if that was enough.
Any insight would be very helpful.
I look forward to hearing from someone.
Cheers