Or instead of buying with them, you could have bought yourself and rented to them. This is what I did for the first approx 10 years of property ownership. My first place was even just a 1 bed flat, but had a separate kitchen, so I was able to rent the living room as a second bedroom. At the time, the rental income was enough to pay the mortgage, and tax free under the "Rent A Room" scheme[0]. From some quick calculations, I think this is still a viable approach, although the rental income is unlikely to pay the full mortgage now, and some of the income is likely to be above the tax free threshold.

[0] https://www.gov.uk/government/publications/income-tax-rent-a...