Transferring/selling a land and building contract

My partner and I put a deposit on land and signed a building contract for a house approx 2 years ago.
The land has been delayed a number of times, and does not look like it will title until around July 2020.

In the interim our circumstances have changed somewhat, mostly that our landlord is potentially offering to sell us the house we have been living in for the last 5 years and that we have become quite attached to.

Considering we have now got our money tied up in an upcoming build contract, is there any way of selling or transferring the contract to another buyer?

The house and land is located in the geelong area and is probably currently worth around 50k more than the amount the contract is for.

Is there any way to transfer or sell this contract on the market, or through facebook etc. We are not looking to make money, tho would not be unhappy if we did.
We are just looking at our options to free up our finances.