I'd suggest to you the same to contact your local IO. I also believe that you will need a copy of the Deed of the Land where the house is located, together with a copy of the House Purchasing Agreement (if any), a copy of your father in law's house book and his Consent.
The form like this, can be downloaded from Immigration website or just grab it at the Immigration office. This one was for 2019, not sure if they have a new one.
I see, I believe you will get one as soon as it is more flexible to fly. As I mentioned, the approval is only valid for a month. If you cannot fly in before its expired, the company will need to reprocess it.