It will most likely happen in <13 years.

Since I don't have a mortgage, I expect this to happen in about 4 years investing 50% Fundsmith & 50% Smithson. Fundsmith has compounded at 18.3% in Euros, Smithson slightly more.

Why have you invested your money?

So I don't need to work.

So you do use money to buy things?

For me, it would be 6 years with an 18.3% return.

Ouch. That would correspond to a deposit of well more than 20% though unless my maths are wrong (always a possibility - I nearly failed 1st year university mathematics for chemists!).

I make it 11 years for your return to exceed your property value (assuming no growth in the latter) at 18.3% return.

18.3% compound grows 95.6% in 4 years, why so long ? I calculate a loss of 174% in 6 years

Value of property - not value of deposit!

IE assuming a 20% deposit you'd it to have grown 6 times.

I don't use gearing.

Only because you can't get a mortgage at your age

No problem at all getting a mortgage here at the age of 58!

maybe you forgot that it already 'lost' >90k in the first year.

120k deposit. 600k property. (1/2 share).

(120k+99k) * 1.183^6 = ~600k

It would be a problem if your income was below 1k a month.
I remember when I was working a Swiss Bank was happy to lend me 700k against a property costing 900k, but not against a property costing 1.2 million.