Why get a mortgage? Buy the property outright or buy two outright or buy 2 3 4 outright and the last one with a small mortgage.Tricky one really. I suppose it's akin to the same question the US winners face - do you accept a lump sum with tax on top, or accept it as a kind of annuity - not sure if this was tax free.
Winning 100mil+ is truly life changing, that puts you up there with a host of successful business people or actors/singers etc.
As sad as it sounds, in my thirties a million quid wouldn't really be life changing. It'd provide some financial security - i.e. paying off mortgage. But by the time you've bought a nice car and maybe a few luxury holidays it's pretty much gone - and the car will have an upkeep cost. So really it's just pay for the mortgage, a few smaller luxuries, and then invest the rest for retirement.
You could also find a way to put them into a company, then open another none profit company get a H.A license and rent it out, get the grants to do them up.