One more thing about your simulation, you say you are using a 3% estimate rent increase per year, but your formulas are actually using 9% per year.

That’s because from year N to year N+1 you consider that your tenants will pay rent worth 12% of the property value after inflation (+6% from previous year) and will on top will pay a 3% rent increase (you also add the 12% return on the additional 2.89 properties you will purchase).

Gross income on year 2 : 11.47 = 12% x (85 + 5.1 + 2.89) + 0.31

I don’t know the UK student accommodation market, but a 9% increase per year for the next 30 years seems a bit bullish. Even if this is likely to happen (most likely in a higher general inflation environment), you should just say you are using 9% instead of 3%.

Can you confirm that assumption?

Thanks!