Basic question: What happens if we continue to pay the lease amount, but refuse to leave a property after the lease has expired until we find an alternate place to live?

We are leasing a large (48 acre) property in South Australia under a private agreement with the owner. We pay the owner $1450+GST / week rent. We paid $117,000 deposit for purchase at the start of the lease, which the owner is intending to keep under the terms of the private agreement. The agreement included an option for us to buy the property if we could obtain finance within the 18 month period of the lease. We have been unable to obtain finance. The lease expires on 29July. If we have still not been able to purchase, the owner has directed us to vacate on 29July, which is how the agreement is worded. We have a massive amount of personal effects, furniture, equipment, building materials, 15 horses etc. My wife’s mother also lives with us. She is 74 with emphysema. We have a 13yo daughter and 24yo son also living with us.
We are seeking an alternate place, but it is highly likely it will not be possible for us to move until a couple of months after 29july.
If we have been unable to find another place to move to by 29July and refuse to leave, what can happen? We would continue to pay the full rent amount.
1. Can the owner get police assistance to have us physically removed and forced off the property?
2. What can the owner physically and/or legally do with our possessions, horses, materials etc? EG: can they enter the property and dump our possessions on the street?
3. What is the best course of action for us to take?

Optional Information:
Province: Northern Adelaide suburb, South Australia

Already Tried:
Negotiation with owner, but she is being very stubborn / hard line.