Thanks David. What Service charge would you suggest? The maintenance fee of £1500 per year should cover most improvements, surely? Happy to increase though if you think appropriate.

As long as the property remains functional, there is no reason to believe it would lose its value, especially in nominal terms where even low levels of inflation would erode most of the debt over the long term.

Imagine inflation of just 1%. In 50 years this would halve the value of the debt, meaning that refinancing 50 years later would be much easier.

However, we could easily introduce a Rent to Buy scheme where people can pay in excess of the rental and pay off the capital over time. Either way, The underlying debt represents no problem because you always have a revenue stream (the rents) that can easily cover it