Are you expecting the right reference is for them to buy the 25 ft^2? Or just rent it for the time you're employed there?
Those are my WFH terms. Companies can take those or provide me an office.
Your employer, to the extent they want to agree to this, is renting space from you and you're citing and setting the price to buy it forever as justification. That undermines. Just name your price and see if they take it or counter.